commit e69aaa6d61af39003186415f3581d519e7a290bd
Author: mpabi <mpabi@mpabi.pl>
Date:   Sat May 2 00:53:25 2026 +0200

    Add FreeRTOS heap4 intro card

diff --git a/.gitea/workflows/render-pdf.yml b/.gitea/workflows/render-pdf.yml
new file mode 100644
index 0000000..2362972
--- /dev/null
+++ b/.gitea/workflows/render-pdf.yml
@@ -0,0 +1,63 @@
+name: Render PDF
+
+on:
+  push:
+    branches:
+      - deploy
+  workflow_dispatch:
+
+jobs:
+  render-pdf:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install TeX
+        run: |
+          if ! command -v latexmk >/dev/null 2>&1; then
+            if ! command -v apt-get >/dev/null 2>&1; then
+              echo "latexmk is missing and apt-get is unavailable" >&2
+              exit 1
+            fi
+            if command -v sudo >/dev/null 2>&1; then
+              SUDO=sudo
+            else
+              SUDO=
+            fi
+            $SUDO apt-get update
+            $SUDO apt-get install -y --no-install-recommends \
+              latexmk \
+              texlive-fonts-recommended \
+              texlive-lang-polish \
+              texlive-latex-base \
+              texlive-latex-extra \
+              texlive-latex-recommended
+          fi
+
+      - name: Render PDF with commit metadata
+        run: ./scripts/render_pdf.sh
+
+      - name: Commit rendered PDF
+        run: |
+          set -eu
+          repo_name="${GITHUB_REPOSITORY#*/}"
+          pdf_file="$(find doc/pdf -maxdepth 1 -type f -name '*.pdf' -print -quit)"
+          if [ -z "$pdf_file" ]; then
+            echo "rendered PDF is missing" >&2
+            exit 1
+          fi
+          remote_sha="$(git ls-remote origin refs/heads/deploy | cut -f1)"
+          if [ "$remote_sha" != "$GITHUB_SHA" ]; then
+            echo "deploy advanced from $GITHUB_SHA to $remote_sha; skip publishing stale PDF"
+            exit 0
+          fi
+          git config user.name "gitea-actions"
+          git config user.email "gitea-actions@noreply.local"
+          printf '%s\n' "$GITHUB_SHA" > doc/pdf/source-commit.txt
+          git add -u doc/pdf
+          git add -f "$pdf_file"
+          git add doc/pdf/source-commit.txt
+          git diff --cached --quiet && exit 0
+          git commit -m "Render ${repo_name} PDF for ${GITHUB_SHA::12} [skip actions]"
+          git push origin HEAD:deploy
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..eab3e99
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,18 @@
+*.aux
+*.log
+*.out
+*.fls
+*.fdb_latexmk
+*.synctex.gz
+*.pdf
+build-meta.tex
+.rv/
+.nvim/
+.vim/
+.build/
+.gdb_history
+host-build/
+build/*/prog.bin
+build/*/prog.elf
+build/*/prog.lst
+build/*/prog.map
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..accd3b8
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,112 @@
+RISCV_PREFIX ?= riscv64-unknown-elf-
+
+CC := $(RISCV_PREFIX)gcc
+OBJCOPY := $(RISCV_PREFIX)objcopy
+OBJDUMP := $(RISCV_PREFIX)objdump
+SIZE := $(RISCV_PREFIX)size
+HOST_CC ?= cc
+
+DEBUG ?= 1
+ifeq ($(DEBUG),1)
+  DBGFLAGS := -g3 -ggdb
+else
+  DBGFLAGS :=
+endif
+
+RV_ENV_ROOT ?= /opt/rv-env
+SUPPORT_ROOT ?= $(RV_ENV_ROOT)/vendor/Hazard3
+H3_COMMON ?= $(SUPPORT_ROOT)/test/sim/common
+H3_INIT ?= $(H3_COMMON)/init.S
+LDSCRIPT ?= $(H3_COMMON)/link_hazard3.ld
+LAB_RUNTIME_DIR ?= $(RV_ENV_ROOT)/vendor/lab-runtime
+MEMOPS ?= $(LAB_RUNTIME_DIR)/memops.c
+
+BUILD_ROOT ?= build
+HOST_BUILD_ROOT ?= host-build
+TASKS := \
+	task01_heap_map \
+	task02_free_list \
+	task03_heap_init \
+	task04_alignment \
+	task05_malloc_first_fit \
+	task06_split_block \
+	task07_free_insert \
+	task08_coalescing \
+	task09_config_macros \
+	task10_heap4_demo
+
+ARCH ?= rv32i_zicsr_zifencei
+ABI ?= ilp32
+
+COMMON_FLAGS := -std=c99 -march=$(ARCH) -mabi=$(ABI) -nostdlib -nostartfiles -ffreestanding -fno-builtin -fno-stack-protector $(DBGFLAGS) -Wall -Wextra -Isrc/tasks
+LINK_FLAGS := -Wl,--no-relax -Wl,-T,$(LDSCRIPT)
+LIBS := -lgcc
+EMIT_FLAGS := -std=c99 -march=$(ARCH) -mabi=$(ABI) -O -ffreestanding -fno-builtin -fno-stack-protector -nostdlib -nostartfiles -Wall -Wextra -Isrc/tasks
+CFLAGS_STEP := $(COMMON_FLAGS) -O
+HOST_CFLAGS := -std=c99 -O0 -g -Wall -Wextra -DHOST_PRINTF=1 -Isrc/tasks
+
+.PHONY: all tasks host \
+	task1 task2 task3 task4 task5 task6 task7 task8 task9 task10 \
+	t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 \
+	host-task1 host-task2 host-task3 host-task4 host-task5 host-task6 host-task7 host-task8 host-task9 host-task10 \
+	ht1 ht2 ht3 ht4 ht5 ht6 ht7 ht8 ht9 ht10 \
+	clean check-support $(TASKS)
+
+all: tasks
+tasks: $(TASKS)
+host: $(addprefix $(HOST_BUILD_ROOT)/,$(addsuffix /prog,$(TASKS)))
+
+task1 t1: $(word 1,$(TASKS))
+task2 t2: $(word 2,$(TASKS))
+task3 t3: $(word 3,$(TASKS))
+task4 t4: $(word 4,$(TASKS))
+task5 t5: $(word 5,$(TASKS))
+task6 t6: $(word 6,$(TASKS))
+task7 t7: $(word 7,$(TASKS))
+task8 t8: $(word 8,$(TASKS))
+task9 t9: $(word 9,$(TASKS))
+task10 t10: $(word 10,$(TASKS))
+
+host-task1 ht1: $(HOST_BUILD_ROOT)/$(word 1,$(TASKS))/prog
+host-task2 ht2: $(HOST_BUILD_ROOT)/$(word 2,$(TASKS))/prog
+host-task3 ht3: $(HOST_BUILD_ROOT)/$(word 3,$(TASKS))/prog
+host-task4 ht4: $(HOST_BUILD_ROOT)/$(word 4,$(TASKS))/prog
+host-task5 ht5: $(HOST_BUILD_ROOT)/$(word 5,$(TASKS))/prog
+host-task6 ht6: $(HOST_BUILD_ROOT)/$(word 6,$(TASKS))/prog
+host-task7 ht7: $(HOST_BUILD_ROOT)/$(word 7,$(TASKS))/prog
+host-task8 ht8: $(HOST_BUILD_ROOT)/$(word 8,$(TASKS))/prog
+host-task9 ht9: $(HOST_BUILD_ROOT)/$(word 9,$(TASKS))/prog
+host-task10 ht10: $(HOST_BUILD_ROOT)/$(word 10,$(TASKS))/prog
+
+check-support:
+	@test -f "$(H3_INIT)" || { echo "Missing $(H3_INIT). Run inside rv-env or set RV_ENV_ROOT=/path/to/rv32i-hazard3-env" >&2; exit 1; }
+	@test -f "$(LDSCRIPT)" || { echo "Missing $(LDSCRIPT)." >&2; exit 1; }
+	@test -f "$(MEMOPS)" || { echo "Missing $(MEMOPS)." >&2; exit 1; }
+
+define task_rules
+$(1): $(BUILD_ROOT)/$(1)/prog.bin $(BUILD_ROOT)/$(1)/prog.elf $(BUILD_ROOT)/$(1)/prog.lst $(BUILD_ROOT)/$(1)/$(1).s
+
+$(BUILD_ROOT)/$(1)/prog.elf: crt0.S src/tasks/$(1).c src/tasks/heap4_common.h $(H3_INIT) $(LDSCRIPT) $(MEMOPS) | check-support
+	mkdir -p $$(@D)
+	$(CC) $(CFLAGS_STEP) $(LINK_FLAGS) -Wl,-Map,$(BUILD_ROOT)/$(1)/prog.map -o $$@ $(H3_INIT) crt0.S $(MEMOPS) src/tasks/$(1).c $(LIBS)
+	$(SIZE) -A -x $$@
+
+$(BUILD_ROOT)/$(1)/prog.bin: $(BUILD_ROOT)/$(1)/prog.elf
+	$(OBJCOPY) -O binary $$< $$@
+
+$(BUILD_ROOT)/$(1)/prog.lst: $(BUILD_ROOT)/$(1)/prog.elf
+	$(OBJDUMP) -d -M no-aliases,numeric $$< > $$@
+
+$(BUILD_ROOT)/$(1)/$(1).s: src/tasks/$(1).c src/tasks/heap4_common.h | check-support
+	mkdir -p $$(@D)
+	$(CC) $(EMIT_FLAGS) -S -o $$@ $$<
+
+$(HOST_BUILD_ROOT)/$(1)/prog: src/tasks/$(1).c src/tasks/heap4_common.h
+	mkdir -p $$(@D)
+	$(HOST_CC) $(HOST_CFLAGS) -o $$@ $$<
+endef
+
+$(foreach task,$(TASKS),$(eval $(call task_rules,$(task))))
+
+clean:
+	rm -rf $(BUILD_ROOT) $(HOST_BUILD_ROOT)
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..4ed2f1e
--- /dev/null
+++ b/README.md
@@ -0,0 +1,45 @@
+# rv32i-freertos / heap4
+
+Karta pracy 1/? z serii `rv32i-freertos`.
+
+Temat: mechanika alokatora `heap_4.c` z FreeRTOS-a na małych przykładach
+uruchamianych w środowisku RV32I.
+
+Ta karta jest pomostem po kartach C: używa wskaźników, struktur, listy
+jednokierunkowej, `static`, `typedef`, makr i arytmetyki adresów, ale nie
+wymaga jeszcze schedulera, tasków ani przerwań.
+
+Kod w `src/tasks` jest dydaktycznym modelem zachowania `heap_4`, a nie kopią
+pliku upstream FreeRTOS.
+
+## Taski
+
+- `task01_heap_map.c` - mapa pojęć: sterta, blok, nagłówek bloku.
+- `task02_free_list.c` - lista wolnych bloków.
+- `task03_heap_init.c` - inicjalizacja sterty i wartownik końca listy.
+- `task04_alignment.c` - wyrównanie rozmiarów i adresów.
+- `task05_malloc_first_fit.c` - pierwszy pasujący wolny blok.
+- `task06_split_block.c` - podział większego bloku.
+- `task07_free_insert.c` - zwracanie bloku na listę wolnych.
+- `task08_coalescing.c` - scalanie sąsiednich wolnych bloków.
+- `task09_config_macros.c` - makra konfiguracyjne i warunkowy `printf`.
+- `task10_heap4_demo.c` - mini-demonstracja `malloc/free` bez pełnego RTOS-a.
+
+Hostowe `printf` jest dostępne tylko przez `-DHOST_PRINTF=1`; RV32I zapisuje
+wyniki w globalnych zmiennych `volatile`.
+
+## Budowanie
+
+```bash
+RV_ENV_ROOT=~/dev/workspace/rv/tools/rv32i-hazard3-student-env make tasks
+make host
+```
+
+## Praca przez rvctl
+
+```bash
+./rvctl series cards fetch inf heap4
+./rvctl card use inf heap4
+./rvctl tasks list
+./rvctl debug rv32i 1
+```
diff --git a/build/task01_heap_map/task01_heap_map.s b/build/task01_heap_map/task01_heap_map.s
new file mode 100644
index 0000000..dea13e1
--- /dev/null
+++ b/build/task01_heap_map/task01_heap_map.s
@@ -0,0 +1,53 @@
+	.file	"task01_heap_map.c"
+	.option nopic
+	.attribute arch, "rv32i2p1_zicsr2p0_zifencei2p0"
+	.attribute unaligned_access, 0
+	.attribute stack_align, 16
+	.text
+	.align	2
+	.globl	main
+	.type	main, @function
+main:
+	li	a5,8
+	sw	a5,g_header_size,a4
+	sw	a5,g_aligned_header_size,a4
+	li	a5,1
+	sw	a5,g_allocated_bit_set,a4
+	lla	a5,g_total_block_bytes
+	li	a4,24
+	sw	a4,0(a5)
+	lw	a5,0(a5)
+	addi	a5,a5,-8
+	sw	a5,g_user_bytes,a4
+	li	a0,0
+	ret
+	.size	main, .-main
+	.globl	g_total_block_bytes
+	.globl	g_user_bytes
+	.globl	g_allocated_bit_set
+	.globl	g_aligned_header_size
+	.globl	g_header_size
+	.section	.sbss,"aw",@nobits
+	.align	2
+	.type	g_total_block_bytes, @object
+	.size	g_total_block_bytes, 4
+g_total_block_bytes:
+	.zero	4
+	.type	g_user_bytes, @object
+	.size	g_user_bytes, 4
+g_user_bytes:
+	.zero	4
+	.type	g_allocated_bit_set, @object
+	.size	g_allocated_bit_set, 4
+g_allocated_bit_set:
+	.zero	4
+	.type	g_aligned_header_size, @object
+	.size	g_aligned_header_size, 4
+g_aligned_header_size:
+	.zero	4
+	.type	g_header_size, @object
+	.size	g_header_size, 4
+g_header_size:
+	.zero	4
+	.ident	"GCC: (15.2.0-23) 15.2.0"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/build/task02_free_list/task02_free_list.s b/build/task02_free_list/task02_free_list.s
new file mode 100644
index 0000000..5dd5d99
--- /dev/null
+++ b/build/task02_free_list/task02_free_list.s
@@ -0,0 +1,73 @@
+	.file	"task02_free_list.c"
+	.option nopic
+	.attribute arch, "rv32i2p1_zicsr2p0_zifencei2p0"
+	.attribute unaligned_access, 0
+	.attribute stack_align, 16
+	.text
+	.align	2
+	.globl	main
+	.type	main, @function
+main:
+	addi	sp,sp,-32
+	addi	a5,sp,16
+	sw	a5,24(sp)
+	li	a5,32
+	sw	a5,28(sp)
+	addi	a5,sp,8
+	sw	a5,16(sp)
+	li	a5,80
+	sw	a5,20(sp)
+	sw	zero,8(sp)
+	li	a5,24
+	sw	a5,12(sp)
+	li	a4,0
+	add	a5,sp,a5
+.L2:
+	lw	a3,4(a5)
+	add	a4,a4,a3
+	lw	a5,0(a5)
+	bne	a5,zero,.L2
+	sw	a4,g_free_total,a5
+	li	a3,0
+	addi	a5,sp,24
+	j	.L4
+.L3:
+	lw	a5,0(a5)
+	beq	a5,zero,.L10
+.L4:
+	lw	a4,4(a5)
+	bgeu	a3,a4,.L3
+	mv	a3,a4
+	j	.L3
+.L10:
+	sw	a3,g_largest_free,a5
+	addi	a5,sp,24
+	li	a4,0
+.L5:
+	addi	a4,a4,1
+	lw	a5,0(a5)
+	bne	a5,zero,.L5
+	sw	a4,g_node_count,a5
+	li	a0,0
+	addi	sp,sp,32
+	jr	ra
+	.size	main, .-main
+	.globl	g_node_count
+	.globl	g_largest_free
+	.globl	g_free_total
+	.section	.sbss,"aw",@nobits
+	.align	2
+	.type	g_node_count, @object
+	.size	g_node_count, 4
+g_node_count:
+	.zero	4
+	.type	g_largest_free, @object
+	.size	g_largest_free, 4
+g_largest_free:
+	.zero	4
+	.type	g_free_total, @object
+	.size	g_free_total, 4
+g_free_total:
+	.zero	4
+	.ident	"GCC: (15.2.0-23) 15.2.0"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/build/task03_heap_init/task03_heap_init.s b/build/task03_heap_init/task03_heap_init.s
new file mode 100644
index 0000000..cffae9f
--- /dev/null
+++ b/build/task03_heap_init/task03_heap_init.s
@@ -0,0 +1,74 @@
+	.file	"task03_heap_init.c"
+	.option nopic
+	.attribute arch, "rv32i2p1_zicsr2p0_zifencei2p0"
+	.attribute unaligned_access, 0
+	.attribute stack_align, 16
+	.text
+	.align	2
+	.globl	main
+	.type	main, @function
+main:
+	lla	a2,.LANCHOR0
+	andi	a4,a2,7
+	mv	a5,a2
+	beq	a4,zero,.L2
+	andi	a5,a2,-8
+	addi	a5,a5,8
+.L2:
+	lla	a3,.LANCHOR0+160
+	sub	a3,a3,a5
+	addi	a4,a5,-8
+	andi	a3,a3,-8
+	add	a4,a4,a3
+	sw	a4,end_marker,a3
+	sw	zero,0(a4)
+	sw	zero,4(a4)
+	sw	a4,0(a5)
+	sub	a3,a4,a5
+	sw	a3,4(a5)
+	lla	a1,start
+	sw	a5,0(a1)
+	sw	zero,4(a1)
+	sub	a5,a5,a2
+	sw	a5,g_aligned_offset,a2
+	sw	a3,g_initial_free_size,a5
+	lw	a5,0(a4)
+	seqz	a5,a5
+	sw	a5,g_end_is_last,a4
+	li	a0,0
+	ret
+	.size	main, .-main
+	.globl	g_end_is_last
+	.globl	g_aligned_offset
+	.globl	g_initial_free_size
+	.bss
+	.align	2
+	.set	.LANCHOR0,. + 0
+	.type	heap_area, @object
+	.size	heap_area, 168
+heap_area:
+	.zero	168
+	.section	.sbss,"aw",@nobits
+	.align	2
+	.type	g_end_is_last, @object
+	.size	g_end_is_last, 4
+g_end_is_last:
+	.zero	4
+	.type	g_aligned_offset, @object
+	.size	g_aligned_offset, 4
+g_aligned_offset:
+	.zero	4
+	.type	g_initial_free_size, @object
+	.size	g_initial_free_size, 4
+g_initial_free_size:
+	.zero	4
+	.type	end_marker, @object
+	.size	end_marker, 4
+end_marker:
+	.zero	4
+	.type	start, @object
+	.size	start, 8
+start:
+	.zero	8
+	.ident	"GCC: (15.2.0-23) 15.2.0"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/build/task04_alignment/task04_alignment.s b/build/task04_alignment/task04_alignment.s
new file mode 100644
index 0000000..db04ead
--- /dev/null
+++ b/build/task04_alignment/task04_alignment.s
@@ -0,0 +1,47 @@
+	.file	"task04_alignment.c"
+	.option nopic
+	.attribute arch, "rv32i2p1_zicsr2p0_zifencei2p0"
+	.attribute unaligned_access, 0
+	.attribute stack_align, 16
+	.text
+	.align	2
+	.globl	main
+	.type	main, @function
+main:
+	addi	sp,sp,-32
+	li	a5,16
+	sw	a5,g_request_1,a4
+	li	a5,24
+	sw	a5,g_request_9,a4
+	li	a5,32
+	sw	a5,g_request_17,a4
+	li	a5,7
+	sw	a5,g_address_delta,a4
+	li	a0,0
+	addi	sp,sp,32
+	jr	ra
+	.size	main, .-main
+	.globl	g_address_delta
+	.globl	g_request_17
+	.globl	g_request_9
+	.globl	g_request_1
+	.section	.sbss,"aw",@nobits
+	.align	2
+	.type	g_address_delta, @object
+	.size	g_address_delta, 4
+g_address_delta:
+	.zero	4
+	.type	g_request_17, @object
+	.size	g_request_17, 4
+g_request_17:
+	.zero	4
+	.type	g_request_9, @object
+	.size	g_request_9, 4
+g_request_9:
+	.zero	4
+	.type	g_request_1, @object
+	.size	g_request_1, 4
+g_request_1:
+	.zero	4
+	.ident	"GCC: (15.2.0-23) 15.2.0"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/build/task05_malloc_first_fit/task05_malloc_first_fit.s b/build/task05_malloc_first_fit/task05_malloc_first_fit.s
new file mode 100644
index 0000000..34fc98e
--- /dev/null
+++ b/build/task05_malloc_first_fit/task05_malloc_first_fit.s
@@ -0,0 +1,95 @@
+	.file	"task05_malloc_first_fit.c"
+	.option nopic
+	.attribute arch, "rv32i2p1_zicsr2p0_zifencei2p0"
+	.attribute unaligned_access, 0
+	.attribute stack_align, 16
+	.text
+	.align	2
+	.globl	main
+	.type	main, @function
+main:
+	lla	a4,.LANCHOR0
+	andi	a5,a4,7
+	beq	a5,zero,.L2
+	andi	a4,a4,-8
+	addi	a4,a4,8
+.L2:
+	mv	a5,a4
+	addi	a3,a4,120
+	sw	a3,end_marker,a2
+	sw	zero,120(a4)
+	sw	zero,4(a3)
+	sw	a3,0(a4)
+	li	a2,120
+	sw	a2,4(a4)
+	lla	a2,start
+	sw	a4,0(a2)
+	sw	zero,4(a2)
+	li	a1,31
+	j	.L5
+.L6:
+	mv	a5,a4
+.L5:
+	lw	a4,4(a5)
+	bgtu	a4,a1,.L7
+	lw	a4,0(a5)
+	mv	a2,a5
+	bne	a4,a3,.L6
+	li	a5,0
+	j	.L4
+.L7:
+	lw	a4,0(a5)
+	sw	a4,0(a2)
+	sw	zero,0(a5)
+	lw	a4,4(a5)
+	li	a3,-2147483648
+	or	a4,a4,a3
+	sw	a4,4(a5)
+	addi	a5,a5,8
+.L4:
+	snez	a4,a5
+	sw	a4,g_allocation_ok,a3
+	lw	a5,-4(a5)
+	slli	a5,a5,1
+	srli	a5,a5,1
+	sw	a5,g_allocated_size,a4
+	lw	a5,start
+	lw	a5,4(a5)
+	sw	a5,g_remaining_free,a4
+	li	a0,0
+	ret
+	.size	main, .-main
+	.globl	g_allocation_ok
+	.globl	g_remaining_free
+	.globl	g_allocated_size
+	.bss
+	.align	2
+	.set	.LANCHOR0,. + 0
+	.type	heap_area, @object
+	.size	heap_area, 136
+heap_area:
+	.zero	136
+	.section	.sbss,"aw",@nobits
+	.align	2
+	.type	g_allocation_ok, @object
+	.size	g_allocation_ok, 4
+g_allocation_ok:
+	.zero	4
+	.type	g_remaining_free, @object
+	.size	g_remaining_free, 4
+g_remaining_free:
+	.zero	4
+	.type	g_allocated_size, @object
+	.size	g_allocated_size, 4
+g_allocated_size:
+	.zero	4
+	.type	end_marker, @object
+	.size	end_marker, 4
+end_marker:
+	.zero	4
+	.type	start, @object
+	.size	start, 8
+start:
+	.zero	8
+	.ident	"GCC: (15.2.0-23) 15.2.0"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/build/task06_split_block/task06_split_block.s b/build/task06_split_block/task06_split_block.s
new file mode 100644
index 0000000..610dfa4
--- /dev/null
+++ b/build/task06_split_block/task06_split_block.s
@@ -0,0 +1,117 @@
+	.file	"task06_split_block.c"
+	.option nopic
+	.attribute arch, "rv32i2p1_zicsr2p0_zifencei2p0"
+	.attribute unaligned_access, 0
+	.attribute stack_align, 16
+	.text
+	.align	2
+	.globl	main
+	.type	main, @function
+main:
+	lla	a4,.LANCHOR0
+	andi	a5,a4,7
+	beq	a5,zero,.L2
+	andi	a4,a4,-8
+	addi	a4,a4,8
+.L2:
+	mv	a5,a4
+	addi	a3,a4,176
+	sw	a3,end_marker,a2
+	sw	zero,176(a4)
+	sw	zero,4(a3)
+	sw	a3,0(a4)
+	li	a2,176
+	sw	a2,4(a4)
+	lla	a2,start
+	sw	a4,0(a2)
+	sw	zero,4(a2)
+	li	a1,39
+	j	.L7
+.L10:
+	mv	a5,a4
+.L7:
+	lw	a4,4(a5)
+	bgtu	a4,a1,.L13
+	lw	a4,0(a5)
+	mv	a2,a5
+	bne	a4,a3,.L10
+	li	a5,0
+	j	.L6
+.L13:
+	addi	a4,a4,-40
+	li	a1,16
+	bleu	a4,a1,.L4
+	sw	a4,44(a5)
+	lw	a4,0(a5)
+	sw	a4,40(a5)
+	addi	a4,a5,40
+	sw	a4,0(a2)
+	li	a4,40
+	sw	a4,4(a5)
+.L5:
+	sw	zero,0(a5)
+	lw	a4,4(a5)
+	li	a2,-2147483648
+	or	a4,a4,a2
+	sw	a4,4(a5)
+	addi	a5,a5,8
+.L6:
+	lw	a5,-4(a5)
+	slli	a5,a5,1
+	srli	a5,a5,1
+	sw	a5,g_allocated_size,a4
+	lw	a5,start
+	lw	a4,4(a5)
+	sw	a4,g_split_free_size,a2
+	beq	a5,a3,.L11
+	li	a4,0
+.L9:
+	addi	a4,a4,1
+	lw	a5,0(a5)
+	bne	a5,a3,.L9
+.L8:
+	sw	a4,g_free_nodes,a5
+	li	a0,0
+	ret
+.L4:
+	lw	a4,0(a5)
+	sw	a4,0(a2)
+	j	.L5
+.L11:
+	li	a4,0
+	j	.L8
+	.size	main, .-main
+	.globl	g_free_nodes
+	.globl	g_split_free_size
+	.globl	g_allocated_size
+	.bss
+	.align	2
+	.set	.LANCHOR0,. + 0
+	.type	heap_area, @object
+	.size	heap_area, 200
+heap_area:
+	.zero	200
+	.section	.sbss,"aw",@nobits
+	.align	2
+	.type	g_free_nodes, @object
+	.size	g_free_nodes, 4
+g_free_nodes:
+	.zero	4
+	.type	g_split_free_size, @object
+	.size	g_split_free_size, 4
+g_split_free_size:
+	.zero	4
+	.type	g_allocated_size, @object
+	.size	g_allocated_size, 4
+g_allocated_size:
+	.zero	4
+	.type	end_marker, @object
+	.size	end_marker, 4
+end_marker:
+	.zero	4
+	.type	start, @object
+	.size	start, 8
+start:
+	.zero	8
+	.ident	"GCC: (15.2.0-23) 15.2.0"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/build/task07_free_insert/task07_free_insert.s b/build/task07_free_insert/task07_free_insert.s
new file mode 100644
index 0000000..4dd5308
--- /dev/null
+++ b/build/task07_free_insert/task07_free_insert.s
@@ -0,0 +1,116 @@
+	.file	"task07_free_insert.c"
+	.option nopic
+	.attribute arch, "rv32i2p1_zicsr2p0_zifencei2p0"
+	.attribute unaligned_access, 0
+	.attribute stack_align, 16
+	.text
+	.align	2
+	.globl	main
+	.type	main, @function
+main:
+	lla	a5,.LANCHOR0
+	lla	a4,.LANCHOR0+176
+	sw	a4,end_marker,a3
+	sw	a5,start,a3
+	lla	a3,.LANCHOR0+128
+	sw	a3,0(a5)
+	sw	a4,128(a5)
+	sw	zero,176(a5)
+	li	a4,40
+	sw	a4,4(a5)
+	li	a4,48
+	sw	a4,132(a5)
+	sw	zero,180(a5)
+	li	a4,32
+	sw	a4,68(a5)
+	lla	a5,start
+	lla	a3,.LANCHOR0+64
+.L2:
+	mv	a4,a5
+	lw	a5,0(a5)
+	bltu	a5,a3,.L2
+	lla	a3,.LANCHOR0
+	sw	a5,64(a3)
+	lla	a5,.LANCHOR0+64
+	sw	a5,0(a4)
+	lw	a5,start
+	beq	a5,a3,.L16
+	sw	zero,g_order_ok,a4
+	lla	a4,.LANCHOR0+176
+	beq	a5,a4,.L5
+.L9:
+	mv	a4,a5
+	li	a3,0
+	lla	a2,.LANCHOR0+176
+.L6:
+	addi	a3,a3,1
+	lw	a4,0(a4)
+	bne	a4,a2,.L6
+	sw	a3,g_free_count,a4
+	li	a4,0
+	lla	a2,.LANCHOR0+176
+.L7:
+	lw	a3,4(a5)
+	add	a4,a4,a3
+	lw	a5,0(a5)
+	bne	a5,a2,.L7
+.L8:
+	sw	a4,g_total_free,a5
+	li	a0,0
+	ret
+.L16:
+	lla	a3,.LANCHOR0+64
+	lw	a2,.LANCHOR0
+	li	a4,0
+	beq	a2,a3,.L17
+.L4:
+	sw	a4,g_order_ok,a3
+	j	.L9
+.L17:
+	lla	a3,.LANCHOR0+128
+	lw	a2,.LANCHOR0+64
+	bne	a2,a3,.L4
+	lla	a3,.LANCHOR0+176
+	lw	a4,.LANCHOR0+128
+	sub	a4,a4,a3
+	seqz	a4,a4
+	j	.L4
+.L5:
+	sw	zero,g_free_count,a5
+	li	a4,0
+	j	.L8
+	.size	main, .-main
+	.globl	g_total_free
+	.globl	g_free_count
+	.globl	g_order_ok
+	.bss
+	.align	2
+	.set	.LANCHOR0,. + 0
+	.type	heap_area, @object
+	.size	heap_area, 192
+heap_area:
+	.zero	192
+	.section	.sbss,"aw",@nobits
+	.align	2
+	.type	g_total_free, @object
+	.size	g_total_free, 4
+g_total_free:
+	.zero	4
+	.type	g_free_count, @object
+	.size	g_free_count, 4
+g_free_count:
+	.zero	4
+	.type	g_order_ok, @object
+	.size	g_order_ok, 4
+g_order_ok:
+	.zero	4
+	.type	end_marker, @object
+	.size	end_marker, 4
+end_marker:
+	.zero	4
+	.type	start, @object
+	.size	start, 8
+start:
+	.zero	8
+	.ident	"GCC: (15.2.0-23) 15.2.0"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/build/task08_coalescing/task08_coalescing.s b/build/task08_coalescing/task08_coalescing.s
new file mode 100644
index 0000000..a60e79e
--- /dev/null
+++ b/build/task08_coalescing/task08_coalescing.s
@@ -0,0 +1,116 @@
+	.file	"task08_coalescing.c"
+	.option nopic
+	.attribute arch, "rv32i2p1_zicsr2p0_zifencei2p0"
+	.attribute unaligned_access, 0
+	.attribute stack_align, 16
+	.text
+	.align	2
+	.globl	main
+	.type	main, @function
+main:
+	lla	a5,.LANCHOR0
+	lla	a4,.LANCHOR0+160
+	sw	a4,end_marker,a3
+	sw	a5,start,a3
+	lla	a3,.LANCHOR0+96
+	sw	a3,0(a5)
+	sw	a4,96(a5)
+	sw	zero,160(a5)
+	li	a4,48
+	sw	a4,4(a5)
+	sw	a4,52(a5)
+	li	a4,64
+	sw	a4,100(a5)
+	sw	zero,164(a5)
+	lla	a5,start
+	lla	a3,.LANCHOR0+48
+.L2:
+	mv	a4,a5
+	lw	a5,0(a5)
+	bltu	a5,a3,.L2
+	lla	a3,.LANCHOR0+96
+	beq	a5,a3,.L12
+.L3:
+	sw	a5,.LANCHOR0+48,a3
+	lla	a5,start
+	lla	a3,.LANCHOR0+48
+	beq	a4,a5,.L4
+	lw	a2,4(a4)
+	slli	a5,a2,1
+	srli	a5,a5,1
+	add	a5,a4,a5
+	beq	a5,a3,.L13
+.L4:
+	sw	a3,0(a4)
+	lw	a2,start
+	lla	a5,.LANCHOR0+160
+	beq	a2,a5,.L9
+	mv	a5,a2
+	li	a4,0
+	lla	a3,.LANCHOR0+160
+.L6:
+	addi	a4,a4,1
+	lw	a5,0(a5)
+	bne	a5,a3,.L6
+.L5:
+	sw	a4,g_free_count,a5
+	lw	a5,4(a2)
+	sw	a5,g_merged_size,a4
+	lw	a5,0(a2)
+	lla	a4,.LANCHOR0+160
+	sub	a5,a5,a4
+	seqz	a5,a5
+	sw	a5,g_merged_with_right,a4
+	li	a0,0
+	ret
+.L12:
+	li	a5,112
+	sw	a5,.LANCHOR0+52,a3
+	lw	a5,0(a4)
+	lw	a5,0(a5)
+	j	.L3
+.L13:
+	lla	a3,.LANCHOR0
+	lw	a5,52(a3)
+	add	a5,a5,a2
+	sw	a5,4(a4)
+	lw	a3,48(a3)
+	j	.L4
+.L9:
+	li	a4,0
+	j	.L5
+	.size	main, .-main
+	.globl	g_merged_with_right
+	.globl	g_merged_size
+	.globl	g_free_count
+	.bss
+	.align	2
+	.set	.LANCHOR0,. + 0
+	.type	heap_area, @object
+	.size	heap_area, 192
+heap_area:
+	.zero	192
+	.section	.sbss,"aw",@nobits
+	.align	2
+	.type	g_merged_with_right, @object
+	.size	g_merged_with_right, 4
+g_merged_with_right:
+	.zero	4
+	.type	g_merged_size, @object
+	.size	g_merged_size, 4
+g_merged_size:
+	.zero	4
+	.type	g_free_count, @object
+	.size	g_free_count, 4
+g_free_count:
+	.zero	4
+	.type	end_marker, @object
+	.size	end_marker, 4
+end_marker:
+	.zero	4
+	.type	start, @object
+	.size	start, 8
+start:
+	.zero	8
+	.ident	"GCC: (15.2.0-23) 15.2.0"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/build/task09_config_macros/task09_config_macros.s b/build/task09_config_macros/task09_config_macros.s
new file mode 100644
index 0000000..de74cea
--- /dev/null
+++ b/build/task09_config_macros/task09_config_macros.s
@@ -0,0 +1,44 @@
+	.file	"task09_config_macros.c"
+	.option nopic
+	.attribute arch, "rv32i2p1_zicsr2p0_zifencei2p0"
+	.attribute unaligned_access, 0
+	.attribute stack_align, 16
+	.text
+	.align	2
+	.globl	main
+	.type	main, @function
+main:
+	li	a5,256
+	sw	a5,g_total_heap,a4
+	li	a5,248
+	sw	a5,g_adjusted_heap,a4
+	li	a5,1
+	sw	a5,g_dynamic_enabled,a4
+	sw	zero,g_trace_is_host_only,a5
+	li	a0,0
+	ret
+	.size	main, .-main
+	.globl	g_trace_is_host_only
+	.globl	g_dynamic_enabled
+	.globl	g_adjusted_heap
+	.globl	g_total_heap
+	.section	.sbss,"aw",@nobits
+	.align	2
+	.type	g_trace_is_host_only, @object
+	.size	g_trace_is_host_only, 4
+g_trace_is_host_only:
+	.zero	4
+	.type	g_dynamic_enabled, @object
+	.size	g_dynamic_enabled, 4
+g_dynamic_enabled:
+	.zero	4
+	.type	g_adjusted_heap, @object
+	.size	g_adjusted_heap, 4
+g_adjusted_heap:
+	.zero	4
+	.type	g_total_heap, @object
+	.size	g_total_heap, 4
+g_total_heap:
+	.zero	4
+	.ident	"GCC: (15.2.0-23) 15.2.0"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/build/task10_heap4_demo/task10_heap4_demo.s b/build/task10_heap4_demo/task10_heap4_demo.s
new file mode 100644
index 0000000..215bceb
--- /dev/null
+++ b/build/task10_heap4_demo/task10_heap4_demo.s
@@ -0,0 +1,253 @@
+	.file	"task10_heap4_demo.c"
+	.option nopic
+	.attribute arch, "rv32i2p1_zicsr2p0_zifencei2p0"
+	.attribute unaligned_access, 0
+	.attribute stack_align, 16
+	.text
+	.align	2
+	.type	heap_malloc_model, @function
+heap_malloc_model:
+	beq	a0,zero,.L1
+	addi	a4,a0,8
+	andi	a0,a0,7
+	beq	a0,zero,.L3
+	andi	a4,a4,-8
+	addi	a4,a4,8
+.L3:
+	lw	a0,start
+	lw	a3,end_marker
+	beq	a0,a3,.L10
+	lla	a2,start
+	j	.L8
+.L11:
+	mv	a0,a5
+.L8:
+	lw	a5,4(a0)
+	bgeu	a5,a4,.L12
+	lw	a5,0(a0)
+	mv	a2,a0
+	bne	a5,a3,.L11
+	li	a0,0
+	ret
+.L12:
+	sub	a3,a5,a4
+	li	a1,16
+	bleu	a3,a1,.L5
+	add	a5,a0,a4
+	sw	a3,4(a5)
+	lw	a3,0(a0)
+	sw	a3,0(a5)
+	sw	a5,0(a2)
+	sw	a4,4(a0)
+.L6:
+	sw	zero,0(a0)
+	lw	a5,4(a0)
+	li	a3,-2147483648
+	or	a5,a5,a3
+	sw	a5,4(a0)
+	lla	a3,free_bytes_remaining
+	lw	a5,0(a3)
+	sub	a5,a5,a4
+	sw	a5,0(a3)
+	lw	a4,minimum_ever_free
+	bgeu	a5,a4,.L7
+	sw	a5,minimum_ever_free,a4
+.L7:
+	addi	a0,a0,8
+	ret
+.L5:
+	lw	a4,0(a0)
+	sw	a4,0(a2)
+	mv	a4,a5
+	j	.L6
+.L10:
+	li	a0,0
+.L1:
+	ret
+	.size	heap_malloc_model, .-heap_malloc_model
+	.align	2
+	.type	heap_free_model, @function
+heap_free_model:
+	beq	a0,zero,.L13
+	lw	a5,-4(a0)
+	blt	a5,zero,.L19
+.L13:
+	ret
+.L19:
+	addi	a3,a0,-8
+	slli	a5,a5,1
+	srli	a2,a5,1
+	sw	a2,-4(a0)
+	lla	a4,free_bytes_remaining
+	lw	a5,0(a4)
+	add	a5,a5,a2
+	sw	a5,0(a4)
+	lla	a5,start
+.L15:
+	mv	a4,a5
+	lw	a5,0(a5)
+	bgtu	a3,a5,.L15
+	add	a1,a3,a2
+	beq	a5,a1,.L20
+.L16:
+	sw	a5,-8(a0)
+	lla	a5,start
+	beq	a4,a5,.L17
+	lw	a2,4(a4)
+	slli	a5,a2,1
+	srli	a5,a5,1
+	add	a5,a4,a5
+	beq	a3,a5,.L21
+.L17:
+	sw	a3,0(a4)
+	ret
+.L20:
+	lw	a5,4(a5)
+	add	a5,a5,a2
+	sw	a5,-4(a0)
+	lw	a5,0(a4)
+	lw	a5,0(a5)
+	j	.L16
+.L21:
+	lw	a5,-4(a0)
+	add	a5,a5,a2
+	sw	a5,4(a4)
+	lw	a5,-8(a0)
+	sw	a5,0(a4)
+	ret
+	.size	heap_free_model, .-heap_free_model
+	.align	2
+	.globl	main
+	.type	main, @function
+main:
+	addi	sp,sp,-32
+	sw	ra,28(sp)
+	sw	s0,24(sp)
+	sw	s1,20(sp)
+	sw	s2,16(sp)
+	sw	s3,12(sp)
+	sw	s4,8(sp)
+	lla	a4,.LANCHOR0
+	andi	a3,a4,7
+	mv	a5,a4
+	beq	a3,zero,.L23
+	andi	a4,a4,-8
+	addi	a5,a4,8
+.L23:
+	lla	s0,.LANCHOR0+256
+	sub	s0,s0,a5
+	andi	s0,s0,-8
+	addi	a4,a5,-8
+	add	s0,s0,a4
+	sw	s0,end_marker,a4
+	sw	zero,0(s0)
+	sw	zero,4(s0)
+	sw	s0,0(a5)
+	sub	a4,s0,a5
+	sw	a4,4(a5)
+	lla	s4,start
+	sw	a5,0(s4)
+	sw	zero,4(s4)
+	sw	a4,free_bytes_remaining,a5
+	sw	a4,minimum_ever_free,a5
+	li	a0,24
+	call	heap_malloc_model
+	mv	s2,a0
+	li	a0,40
+	call	heap_malloc_model
+	mv	s3,a0
+	mv	a0,s2
+	call	heap_free_model
+	li	a0,16
+	call	heap_malloc_model
+	mv	s1,a0
+	mv	a0,s3
+	call	heap_free_model
+	mv	a0,s1
+	call	heap_free_model
+	snez	s2,s2
+	snez	s3,s3
+	and	s2,s2,s3
+	snez	s1,s1
+	and	s1,s1,s2
+	sw	s1,g_allocations_ok,a5
+	lw	a5,0(s4)
+	beq	s0,a5,.L24
+	mv	a4,a5
+	li	a3,0
+.L25:
+	addi	a3,a3,1
+	lw	a4,0(a4)
+	bne	s0,a4,.L25
+	sw	a3,g_final_free_nodes,a2
+	li	a3,0
+.L26:
+	lw	a2,4(a5)
+	add	a3,a3,a2
+	lw	a5,0(a5)
+	bne	a5,a4,.L26
+.L27:
+	sw	a3,g_final_free_total,a5
+	lw	a5,minimum_ever_free
+	sw	a5,g_minimum_ever_free,a4
+	li	a0,0
+	lw	ra,28(sp)
+	lw	s0,24(sp)
+	lw	s1,20(sp)
+	lw	s2,16(sp)
+	lw	s3,12(sp)
+	lw	s4,8(sp)
+	addi	sp,sp,32
+	jr	ra
+.L24:
+	sw	zero,g_final_free_nodes,a5
+	li	a3,0
+	j	.L27
+	.size	main, .-main
+	.globl	g_minimum_ever_free
+	.globl	g_final_free_total
+	.globl	g_final_free_nodes
+	.globl	g_allocations_ok
+	.bss
+	.align	2
+	.set	.LANCHOR0,. + 0
+	.type	heap_area, @object
+	.size	heap_area, 264
+heap_area:
+	.zero	264
+	.section	.sbss,"aw",@nobits
+	.align	2
+	.type	minimum_ever_free, @object
+	.size	minimum_ever_free, 4
+minimum_ever_free:
+	.zero	4
+	.type	free_bytes_remaining, @object
+	.size	free_bytes_remaining, 4
+free_bytes_remaining:
+	.zero	4
+	.type	g_minimum_ever_free, @object
+	.size	g_minimum_ever_free, 4
+g_minimum_ever_free:
+	.zero	4
+	.type	g_final_free_total, @object
+	.size	g_final_free_total, 4
+g_final_free_total:
+	.zero	4
+	.type	g_final_free_nodes, @object
+	.size	g_final_free_nodes, 4
+g_final_free_nodes:
+	.zero	4
+	.type	g_allocations_ok, @object
+	.size	g_allocations_ok, 4
+g_allocations_ok:
+	.zero	4
+	.type	end_marker, @object
+	.size	end_marker, 4
+end_marker:
+	.zero	4
+	.type	start, @object
+	.size	start, 8
+start:
+	.zero	8
+	.ident	"GCC: (15.2.0-23) 15.2.0"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/crt0.S b/crt0.S
new file mode 100644
index 0000000..86409d3
--- /dev/null
+++ b/crt0.S
@@ -0,0 +1,33 @@
+  .text
+  .global _start
+  .type   _start, @function
+
+_start:
+  # Initialize global pointer.
+.option push
+.option norelax
+  la      gp, __global_pointer$
+.option pop
+
+  # Stack pointer is intentionally not set here.
+  # In the Hazard3 testbench flow, common/init.S enters _start with sp
+  # already loaded from __stack_top and adjusted to leave the argc/argv
+  # area expected by newlib-style startup code.
+
+  # Clear the .bss segment so debug globals start in a known state.
+  la      a0, __bss_start
+  la      a1, __bss_end
+
+clear_bss:
+  bgeu    a0, a1, finish_bss
+  sb      x0, 0(a0)
+  addi    a0, a0, 1
+  j       clear_bss
+finish_bss:
+
+  call    main
+
+  # Exit the testbench with main() return code (Hazard3 init.S provides _exit).
+  tail    _exit
+
+  .size  _start, .-_start
diff --git a/doc/main.tex b/doc/main.tex
new file mode 100644
index 0000000..df43bfe
--- /dev/null
+++ b/doc/main.tex
@@ -0,0 +1,153 @@
+\documentclass[12pt]{article}
+\usepackage[T1]{fontenc}
+\usepackage[utf8]{inputenc}
+\usepackage[polish]{babel}
+\usepackage[a4paper,margin=2.0cm]{geometry}
+\usepackage{array}
+\usepackage{tabularx}
+\usepackage{xcolor}
+\usepackage{listings}
+\usepackage{hyperref}
+\usepackage{fancyhdr}
+\usepackage{lastpage}
+\usepackage{enumitem}
+
+\definecolor{accent}{HTML}{16324A}
+\definecolor{accentlight}{HTML}{EEF3F7}
+\definecolor{rulegray}{HTML}{D7DEE5}
+\hypersetup{colorlinks=true,linkcolor=blue,urlcolor=blue,citecolor=blue}
+\IfFileExists{build-meta.tex}{\input{build-meta.tex}}{\newcommand{\BuildCommit}{local}}
+\newcommand{\PublisherDomain}{mpabi}
+\newcommand{\DocumentAuthor}{M. Pabiszczak}
+\newcommand{\DocumentYear}{2026}
+\newcommand{\CardArea}{inf}
+\newcommand{\CardSeries}{rv32i-freertos}
+\newcommand{\CardNumber}{01}
+\newcommand{\CardCount}{??}
+\newcommand{\CardSlug}{heap4}
+\newcommand{\CardVersion}{v0.1}
+\newcommand{\DocumentKey}{\PublisherDomain/\CardArea/\CardSeries/\CardNumber/\CardSlug/\CardVersion}
+\newcommand{\DocumentUUID}{4654524c-73f2-46df-83a3-d448ba6d6c5a}
+\renewcommand{\lstlistingname}{Listing}
+\renewcommand{\lstlistlistingname}{Lista listingów}
+
+\lstset{basicstyle=\ttfamily\small,columns=fullflexible,keepspaces=true,frame=single,breaklines=true,showstringspaces=false,numbers=left,numberstyle=\tiny\color{accent},stepnumber=1,numbersep=8pt,backgroundcolor=\color{accentlight},rulecolor=\color{rulegray},captionpos=b}
+\newcommand{\TaskSection}[4]{\section{Task #1: #3}#4\lstinputlisting[language=C,caption={Task #1: #3},label={lst:task#1-c}]{../src/tasks/#2.c}\lstinputlisting[basicstyle=\ttfamily\scriptsize,caption={ASM dla task #1},label={lst:task#1-asm}]{../build/#2/#2.s}}
+
+\pagestyle{fancy}
+\fancyhf{}
+\lhead{\textbf{FreeRTOS: heap\_4}}
+\rhead{\small \DocumentAuthor, \DocumentYear}
+\lfoot{\scriptsize commit \BuildCommit}
+\cfoot{\scriptsize \thepage/\pageref{LastPage}}
+\rfoot{\scriptsize uuid \DocumentUUID}
+\renewcommand{\headrulewidth}{0.4pt}
+\setlength{\headheight}{18pt}
+\setlength{\footskip}{24pt}
+
+\begin{document}
+\sloppy
+\noindent
+\begin{tabular}{@{}lp{0.72\textwidth}@{}}
+Project: & FreeRTOS: \texttt{heap\_4} \\
+Subject: & Informatyka \\
+Level: & 1, Zakres Podstawowy, PP \\
+Topic: & dynamiczna alokacja pamięci, lista wolnych bloków, scalanie bloków \\
+Revision date: & 02.05.2026 \\
+Status: & Draft \\
+Card in series: & \small\texttt{\CardNumber/\CardCount} \\
+Card version: & \small\texttt{\CardVersion} \\
+Card key: & \small\texttt{\DocumentKey} \\
+UUID: & \small\texttt{\DocumentUUID} \\
+Commit: & \small\texttt{\BuildCommit} \\
+Scope: & pierwsza karta serii FreeRTOS; model dydaktyczny mechaniki \texttt{heap\_4.c} \\
+Files used: & \small
+\begin{tabular}[t]{@{}l@{}}
+Task01: \texttt{task01\_heap\_map.c} \\
+Task02: \texttt{task02\_free\_list.c} \\
+Task03: \texttt{task03\_heap\_init.c} \\
+Task04: \texttt{task04\_alignment.c} \\
+Task05: \texttt{task05\_malloc\_first\_fit.c} \\
+Task06: \texttt{task06\_split\_block.c} \\
+Task07: \texttt{task07\_free\_insert.c} \\
+Task08: \texttt{task08\_coalescing.c} \\
+Task09: \texttt{task09\_config\_macros.c} \\
+Task10: \texttt{task10\_heap4\_demo.c} \\
+Common: \texttt{heap4\_common.h} \\
+Runtime: \texttt{memops.c} \\
+Startup: \texttt{crt0.S}
+\end{tabular}
+\end{tabular}
+
+\vspace{0.8em}
+\noindent\rule{\textwidth}{0.5pt}
+
+\section{Cel}
+Ta karta zaczyna serię FreeRTOS od \texttt{heap\_4}, ponieważ ten plik jest
+naturalnym pomostem po kartach z języka C. Wymaga wskaźników, tablic,
+struktur, listy jednokierunkowej, \texttt{static}, \texttt{typedef}, makr oraz
+arytmetyki adresów, ale nie wymaga jeszcze schedulera, przerwań ani
+uruchamiania tasków.
+
+Przykłady są małym modelem edukacyjnym mechaniki \texttt{heap\_4.c}. Nie są
+kopią pliku upstream FreeRTOS. Na RV32I wyniki są zapisywane w globalnych
+zmiennych \texttt{volatile}; \texttt{printf} jest dostępny wyłącznie w wariancie
+hostowym przez flagę \texttt{-DHOST\_PRINTF=1}.
+
+\lstinputlisting[language=C,caption={Wspólny nagłówek dla karty \texttt{heap\_4}},label={lst:common-h}]{../src/tasks/heap4_common.h}
+
+\subsection{\texttt{static inline} w nagłówku}
+Helpery z Listingu~\ref{lst:common-h} są zapisane jako \texttt{static inline},
+bo każdy task jest osobnym programem i dołącza ten sam nagłówek. \texttt{static}
+daje prywatną kopię funkcji w każdym pliku \texttt{.c}, a \texttt{inline}
+pozwala kompilatorowi wstawić krótkie obliczenia, takie jak wyrównanie rozmiaru
+lub sprawdzenie bitu alokacji, bez kosztu zwykłego wywołania funkcji.
+
+\section{Mapa karty}
+\begin{tabularx}{\textwidth}{|p{2.1cm}|X|}
+\hline
+Task & Temat \\
+\hline
+1 & Mapa pojęć: obszar sterty, nagłówek bloku i bit alokacji. \\
+\hline
+2 & Lista wolnych bloków jako lista jednokierunkowa. \\
+\hline
+3 & Inicjalizacja sterty, pierwszy wolny blok i wartownik końca listy. \\
+\hline
+4 & Wyrównanie rozmiarów żądań i adresu początku sterty. \\
+\hline
+5 & Pierwszy pasujący blok, czyli zasada \texttt{first fit}. \\
+\hline
+6 & Podział dużego bloku na część przydzieloną i pozostały blok wolny. \\
+\hline
+7 & Zwracanie bloku i wstawianie go do listy według adresu. \\
+\hline
+8 & Scalanie sąsiednich wolnych bloków. \\
+\hline
+9 & Makra konfiguracyjne oraz hostowy \texttt{TRACE\_PRINTF}. \\
+\hline
+10 & Mini-demonstracja sekwencji \texttt{malloc/free}. \\
+\hline
+\end{tabularx}
+
+\TaskSection{01}{task01_heap_map}{mapa \texttt{heap\_4}}{Listing~\ref{lst:task01-c} pokazuje nagłówek bloku, wyrównanie rozmiaru i bit oznaczający blok zajęty.}
+\TaskSection{02}{task02_free_list}{lista wolnych bloków}{Listing~\ref{lst:task02-c} przechodzi po liście wolnych bloków i liczy sumę dostępnej pamięci.}
+\TaskSection{03}{task03_heap_init}{inicjalizacja sterty}{Listing~\ref{lst:task03-c} tworzy pierwszy wolny blok oraz końcowy znacznik listy.}
+\TaskSection{04}{task04_alignment}{wyrównanie}{Listing~\ref{lst:task04-c} pokazuje, dlaczego alokator zaokrągla rozmiary i adres początku sterty.}
+\TaskSection{05}{task05_malloc_first_fit}{\texttt{first fit}}{Listing~\ref{lst:task05-c} wybiera pierwszy wolny blok wystarczająco duży dla żądania.}
+\TaskSection{06}{task06_split_block}{podział bloku}{Listing~\ref{lst:task06-c} zostawia resztę dużego bloku na liście wolnych bloków.}
+\TaskSection{07}{task07_free_insert}{\texttt{free} i wstawianie}{Listing~\ref{lst:task07-c} zwraca blok do listy tak, aby lista pozostała posortowana po adresach.}
+\TaskSection{08}{task08_coalescing}{scalanie bloków}{Listing~\ref{lst:task08-c} scala blok z lewym i prawym sąsiadem, gdy adresy są ciągłe.}
+\TaskSection{09}{task09_config_macros}{makra konfiguracyjne}{Listing~\ref{lst:task09-c} pokazuje małe odpowiedniki makr konfiguracyjnych FreeRTOS-a.}
+\TaskSection{10}{task10_heap4_demo}{mini \texttt{heap\_4}}{Listing~\ref{lst:task10-c} łączy inicjalizację, alokację, zwalnianie i scalanie w jeden model.}
+
+\section{Polecenia}
+\begin{enumerate}[leftmargin=1.6em]
+  \item Zbuduj kartę dla RV32I poleceniem \texttt{make tasks}.
+  \item Zbuduj wariant hostowy poleceniem \texttt{make host}; wypisywanie działa tylko przez \texttt{HOST\_PRINTF}.
+  \item W tasku 6 zmień próg \texttt{MIN\_SPLIT\_SIZE} i sprawdź, kiedy blok nie jest dzielony.
+  \item W tasku 8 zmień rozmiary bloków tak, aby scalanie działało tylko z prawym sąsiadem.
+  \item W tasku 10 dodaj większą alokację, która ma się nie udać, i zapisz status w nowej zmiennej \texttt{volatile}.
+\end{enumerate}
+
+\end{document}
diff --git a/doc/pdf/.gitkeep b/doc/pdf/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/scripts/render_pdf.sh b/scripts/render_pdf.sh
new file mode 100755
index 0000000..3aa9027
--- /dev/null
+++ b/scripts/render_pdf.sh
@@ -0,0 +1,70 @@
+#!/usr/bin/env sh
+set -eu
+
+DOC_DIR="doc"
+TEX_FILE="main.tex"
+
+script_dir=$(CDPATH= cd "$(dirname "$0")" && pwd)
+repo_root=$(CDPATH= cd "$script_dir/.." && pwd)
+repo_name="${REPO_NAME:-$(basename "$repo_root")}"
+tex_path="$repo_root/$DOC_DIR/$TEX_FILE"
+
+read_tex_command() {
+  sed -n "s/^\\\\newcommand{\\\\$1}{\\([^}]*\\)}$/\\1/p" "$tex_path" | head -n 1
+}
+
+publisher_domain=$(read_tex_command PublisherDomain)
+card_area=$(read_tex_command CardArea)
+card_series=$(read_tex_command CardSeries)
+card_number=$(read_tex_command CardNumber)
+card_slug=$(read_tex_command CardSlug)
+card_version=$(read_tex_command CardVersion)
+document_uuid=$(read_tex_command DocumentUUID)
+
+if [ -z "$publisher_domain" ] || [ -z "$card_area" ] || [ -z "$card_series" ] || \
+  [ -z "$card_number" ] || [ -z "$card_slug" ] || [ -z "$card_version" ] || \
+  [ -z "$document_uuid" ]; then
+  echo "missing card metadata in $tex_path" >&2
+  exit 1
+fi
+
+commit="${GITEA_SHA:-${GITHUB_SHA:-}}"
+if [ -z "$commit" ]; then
+  commit=$(git -C "$repo_root" rev-parse HEAD)
+fi
+short_commit=$(printf '%s' "$commit" | cut -c1-12)
+
+meta_file="$repo_root/$DOC_DIR/build-meta.tex"
+tmp_meta="$meta_file.tmp.$$"
+cleanup() {
+  rm -f "$meta_file" "$tmp_meta"
+}
+trap cleanup EXIT HUP INT TERM
+
+printf '\\newcommand{\\BuildCommit}{%s}\n' "$short_commit" > "$tmp_meta"
+mv "$tmp_meta" "$meta_file"
+
+pdf_out_dir="${PDF_OUT_DIR:-$repo_root/doc/pdf}"
+mkdir -p "$pdf_out_dir"
+out_dir=$(CDPATH= cd "$pdf_out_dir" && pwd)
+pdf_basename="$publisher_domain-$card_area-$card_series-$card_number-$card_slug-$card_version-$document_uuid.pdf"
+find "$out_dir" -maxdepth 1 -type f -name '*.pdf' -delete
+
+(
+  cd "$repo_root/$DOC_DIR"
+  latexmk -pdf -interaction=nonstopmode -outdir="$out_dir" "$TEX_FILE"
+)
+
+source_pdf="$out_dir/${TEX_FILE%.tex}.pdf"
+target_pdf="$out_dir/$pdf_basename"
+if [ "$source_pdf" != "$target_pdf" ]; then
+  mv "$source_pdf" "$target_pdf"
+fi
+
+find "$out_dir" -maxdepth 1 -type f \( \
+  -name '*.aux' -o \
+  -name '*.log' -o \
+  -name '*.out' -o \
+  -name '*.fls' -o \
+  -name '*.fdb_latexmk' \
+\) -delete
diff --git a/src/tasks/heap4_common.h b/src/tasks/heap4_common.h
new file mode 100644
index 0000000..3d79f9d
--- /dev/null
+++ b/src/tasks/heap4_common.h
@@ -0,0 +1,61 @@
+#ifndef HEAP4_COMMON_H
+#define HEAP4_COMMON_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef HOST_PRINTF
+#include <stdio.h>
+#define TRACE_PRINTF(...) printf(__VA_ARGS__)
+#else
+#define TRACE_PRINTF(...) ((void)0)
+#endif
+
+#define HEAP4_ARRAY_LEN(a) ((int)(sizeof(a) / sizeof((a)[0])))
+#define HEAP4_ALIGNMENT ((size_t)8)
+#define HEAP4_ALIGNMENT_MASK (HEAP4_ALIGNMENT - 1U)
+#define HEAP4_ALLOCATED_BIT ((size_t)1U << (sizeof(size_t) * 8U - 1U))
+
+typedef struct HeapBlock {
+    struct HeapBlock *next;
+    size_t size;
+} HeapBlock;
+
+static inline size_t heap4_align_up(size_t value)
+{
+    if ((value & HEAP4_ALIGNMENT_MASK) != 0U)
+        value += HEAP4_ALIGNMENT - (value & HEAP4_ALIGNMENT_MASK);
+    return value;
+}
+
+static inline uintptr_t heap4_align_address(uintptr_t address)
+{
+    uintptr_t mask;
+
+    mask = (uintptr_t)HEAP4_ALIGNMENT_MASK;
+    if ((address & mask) != 0U)
+        address += (uintptr_t)HEAP4_ALIGNMENT - (address & mask);
+    return address;
+}
+
+static inline size_t heap4_clear_allocated(size_t size)
+{
+    return size & ~HEAP4_ALLOCATED_BIT;
+}
+
+static inline size_t heap4_mark_allocated(size_t size)
+{
+    return size | HEAP4_ALLOCATED_BIT;
+}
+
+static inline int heap4_is_allocated(size_t size)
+{
+    return (size & HEAP4_ALLOCATED_BIT) != 0U;
+}
+
+static inline int heap4_blocks_touch(HeapBlock *left, HeapBlock *right)
+{
+    return (uint8_t *)left + heap4_clear_allocated(left->size) == (uint8_t *)right;
+}
+
+#endif
diff --git a/src/tasks/task01_heap_map.c b/src/tasks/task01_heap_map.c
new file mode 100644
index 0000000..b7c52b7
--- /dev/null
+++ b/src/tasks/task01_heap_map.c
@@ -0,0 +1,29 @@
+#include "heap4_common.h"
+
+volatile size_t g_header_size;
+volatile size_t g_aligned_header_size;
+volatile size_t g_allocated_bit_set;
+volatile size_t g_user_bytes;
+volatile size_t g_total_block_bytes;
+
+int main(void)
+{
+    HeapBlock block;
+    size_t requested;
+
+    requested = 13U;
+    block.next = 0;
+    block.size = heap4_mark_allocated(heap4_align_up(requested + sizeof(HeapBlock)));
+
+    g_header_size = sizeof(HeapBlock);
+    g_aligned_header_size = heap4_align_up(sizeof(HeapBlock));
+    g_allocated_bit_set = heap4_is_allocated(block.size);
+    g_total_block_bytes = heap4_clear_allocated(block.size);
+    g_user_bytes = g_total_block_bytes - sizeof(HeapBlock);
+
+    TRACE_PRINTF("header=%u aligned=%u allocated=%u total=%u user=%u\n",
+                 (unsigned)g_header_size, (unsigned)g_aligned_header_size,
+                 (unsigned)g_allocated_bit_set, (unsigned)g_total_block_bytes,
+                 (unsigned)g_user_bytes);
+    return 0;
+}
diff --git a/src/tasks/task02_free_list.c b/src/tasks/task02_free_list.c
new file mode 100644
index 0000000..eb32284
--- /dev/null
+++ b/src/tasks/task02_free_list.c
@@ -0,0 +1,64 @@
+#include "heap4_common.h"
+
+volatile size_t g_free_total;
+volatile size_t g_largest_free;
+volatile int g_node_count;
+
+static size_t list_total(HeapBlock *start)
+{
+    HeapBlock *block;
+    size_t total;
+
+    total = 0U;
+    for (block = start->next; block != 0; block = block->next)
+        total += block->size;
+    return total;
+}
+
+static size_t list_largest(HeapBlock *start)
+{
+    HeapBlock *block;
+    size_t largest;
+
+    largest = 0U;
+    for (block = start->next; block != 0; block = block->next)
+        if (block->size > largest)
+            largest = block->size;
+    return largest;
+}
+
+static int list_count(HeapBlock *start)
+{
+    HeapBlock *block;
+    int count;
+
+    count = 0;
+    for (block = start->next; block != 0; block = block->next)
+        count++;
+    return count;
+}
+
+int main(void)
+{
+    HeapBlock start;
+    HeapBlock a;
+    HeapBlock b;
+    HeapBlock c;
+
+    start.next = &a;
+    start.size = 0U;
+    a.next = &b;
+    a.size = 32U;
+    b.next = &c;
+    b.size = 80U;
+    c.next = 0;
+    c.size = 24U;
+
+    g_free_total = list_total(&start);
+    g_largest_free = list_largest(&start);
+    g_node_count = list_count(&start);
+
+    TRACE_PRINTF("free=%u largest=%u count=%d\n",
+                 (unsigned)g_free_total, (unsigned)g_largest_free, g_node_count);
+    return 0;
+}
diff --git a/src/tasks/task03_heap_init.c b/src/tasks/task03_heap_init.c
new file mode 100644
index 0000000..eda51c7
--- /dev/null
+++ b/src/tasks/task03_heap_init.c
@@ -0,0 +1,49 @@
+#include "heap4_common.h"
+
+#define HEAP_BYTES 160U
+
+static uint8_t heap_area[HEAP_BYTES + HEAP4_ALIGNMENT];
+static HeapBlock start;
+static HeapBlock *end_marker;
+
+volatile size_t g_initial_free_size;
+volatile uintptr_t g_aligned_offset;
+volatile int g_end_is_last;
+
+static void heap_init(void)
+{
+    uintptr_t raw;
+    uintptr_t aligned;
+    size_t available;
+    HeapBlock *first;
+
+    raw = (uintptr_t)&heap_area[0];
+    aligned = heap4_align_address(raw);
+    available = HEAP_BYTES - (size_t)(aligned - raw);
+    available &= ~HEAP4_ALIGNMENT_MASK;
+
+    first = (HeapBlock *)aligned;
+    end_marker = (HeapBlock *)(aligned + available - sizeof(HeapBlock));
+    end_marker->next = 0;
+    end_marker->size = 0U;
+
+    first->next = end_marker;
+    first->size = (uint8_t *)end_marker - (uint8_t *)first;
+
+    start.next = first;
+    start.size = 0U;
+}
+
+int main(void)
+{
+    heap_init();
+
+    g_aligned_offset = (uintptr_t)start.next - (uintptr_t)&heap_area[0];
+    g_initial_free_size = start.next->size;
+    g_end_is_last = (start.next->next == end_marker) && (end_marker->next == 0);
+
+    TRACE_PRINTF("offset=%u free=%u end_last=%d\n",
+                 (unsigned)g_aligned_offset, (unsigned)g_initial_free_size,
+                 g_end_is_last);
+    return 0;
+}
diff --git a/src/tasks/task04_alignment.c b/src/tasks/task04_alignment.c
new file mode 100644
index 0000000..debb85e
--- /dev/null
+++ b/src/tasks/task04_alignment.c
@@ -0,0 +1,26 @@
+#include "heap4_common.h"
+
+volatile size_t g_request_1;
+volatile size_t g_request_9;
+volatile size_t g_request_17;
+volatile uintptr_t g_address_delta;
+
+int main(void)
+{
+    uint8_t bytes[32];
+    uintptr_t raw;
+    uintptr_t aligned;
+
+    g_request_1 = heap4_align_up(1U + sizeof(HeapBlock));
+    g_request_9 = heap4_align_up(9U + sizeof(HeapBlock));
+    g_request_17 = heap4_align_up(17U + sizeof(HeapBlock));
+
+    raw = (uintptr_t)&bytes[1];
+    aligned = heap4_align_address(raw);
+    g_address_delta = aligned - raw;
+
+    TRACE_PRINTF("r1=%u r9=%u r17=%u delta=%u\n",
+                 (unsigned)g_request_1, (unsigned)g_request_9,
+                 (unsigned)g_request_17, (unsigned)g_address_delta);
+    return 0;
+}
diff --git a/src/tasks/task05_malloc_first_fit.c b/src/tasks/task05_malloc_first_fit.c
new file mode 100644
index 0000000..4303c95
--- /dev/null
+++ b/src/tasks/task05_malloc_first_fit.c
@@ -0,0 +1,73 @@
+#include "heap4_common.h"
+
+#define HEAP_BYTES 128U
+
+static uint8_t heap_area[HEAP_BYTES + HEAP4_ALIGNMENT];
+static HeapBlock start;
+static HeapBlock *end_marker;
+
+volatile size_t g_allocated_size;
+volatile size_t g_remaining_free;
+volatile int g_allocation_ok;
+
+static void heap_init_one_block(void)
+{
+    uintptr_t raw;
+    uintptr_t aligned;
+    HeapBlock *first;
+
+    raw = (uintptr_t)&heap_area[0];
+    aligned = heap4_align_address(raw);
+    first = (HeapBlock *)aligned;
+    end_marker = (HeapBlock *)(aligned + 120U);
+
+    end_marker->next = 0;
+    end_marker->size = 0U;
+    first->next = end_marker;
+    first->size = (uint8_t *)end_marker - (uint8_t *)first;
+    start.next = first;
+    start.size = 0U;
+}
+
+static void *heap_malloc_whole_block(size_t wanted)
+{
+    HeapBlock *previous;
+    HeapBlock *block;
+    size_t total;
+
+    total = heap4_align_up(wanted + sizeof(HeapBlock));
+    previous = &start;
+    block = start.next;
+
+    while (block != end_marker) {
+        if (block->size >= total) {
+            previous->next = block->next;
+            block->next = 0;
+            block->size = heap4_mark_allocated(block->size);
+            return (uint8_t *)block + sizeof(HeapBlock);
+        }
+        previous = block;
+        block = block->next;
+    }
+
+    return 0;
+}
+
+int main(void)
+{
+    void *p;
+    HeapBlock *allocated;
+
+    heap_init_one_block();
+    p = heap_malloc_whole_block(24U);
+    allocated = (HeapBlock *)((uint8_t *)p - sizeof(HeapBlock));
+
+    g_allocation_ok = p != 0;
+    g_allocated_size = heap4_clear_allocated(allocated->size);
+    g_remaining_free = start.next->size;
+
+    TRACE_PRINTF("ok=%d allocated=%u remaining=%u\n",
+                 g_allocation_ok, (unsigned)g_allocated_size,
+                 (unsigned)g_remaining_free);
+    return 0;
+}
diff --git a/src/tasks/task06_split_block.c b/src/tasks/task06_split_block.c
new file mode 100644
index 0000000..49c0d51
--- /dev/null
+++ b/src/tasks/task06_split_block.c
@@ -0,0 +1,93 @@
+#include "heap4_common.h"
+
+#define HEAP_BYTES 192U
+#define MIN_SPLIT_SIZE ((size_t)(sizeof(HeapBlock) * 2U))
+
+static uint8_t heap_area[HEAP_BYTES + HEAP4_ALIGNMENT];
+static HeapBlock start;
+static HeapBlock *end_marker;
+
+volatile size_t g_allocated_size;
+volatile size_t g_split_free_size;
+volatile int g_free_nodes;
+
+static void heap_init_one_block(void)
+{
+    uintptr_t aligned;
+    HeapBlock *first;
+
+    aligned = heap4_align_address((uintptr_t)&heap_area[0]);
+    first = (HeapBlock *)aligned;
+    end_marker = (HeapBlock *)(aligned + 176U);
+    end_marker->next = 0;
+    end_marker->size = 0U;
+    first->next = end_marker;
+    first->size = (uint8_t *)end_marker - (uint8_t *)first;
+    start.next = first;
+    start.size = 0U;
+}
+
+static void *heap_malloc_split(size_t wanted)
+{
+    HeapBlock *previous;
+    HeapBlock *block;
+    HeapBlock *remainder;
+    size_t total;
+    size_t original;
+
+    total = heap4_align_up(wanted + sizeof(HeapBlock));
+    previous = &start;
+    block = start.next;
+
+    while (block != end_marker) {
+        if (block->size >= total) {
+            original = block->size;
+            if (original - total > MIN_SPLIT_SIZE) {
+                remainder = (HeapBlock *)((uint8_t *)block + total);
+                remainder->size = original - total;
+                remainder->next = block->next;
+                previous->next = remainder;
+                block->size = total;
+            } else {
+                previous->next = block->next;
+            }
+            block->next = 0;
+            block->size = heap4_mark_allocated(block->size);
+            return (uint8_t *)block + sizeof(HeapBlock);
+        }
+        previous = block;
+        block = block->next;
+    }
+
+    return 0;
+}
+
+static int count_free_nodes(void)
+{
+    HeapBlock *block;
+    int count;
+
+    count = 0;
+    for (block = start.next; block != end_marker; block = block->next)
+        count++;
+    return count;
+}
+
+int main(void)
+{
+    void *p;
+    HeapBlock *allocated;
+
+    heap_init_one_block();
+    p = heap_malloc_split(32U);
+    allocated = (HeapBlock *)((uint8_t *)p - sizeof(HeapBlock));
+
+    g_allocated_size = heap4_clear_allocated(allocated->size);
+    g_split_free_size = start.next->size;
+    g_free_nodes = count_free_nodes();
+
+    TRACE_PRINTF("allocated=%u split=%u nodes=%d\n",
+                 (unsigned)g_allocated_size, (unsigned)g_split_free_size,
+                 g_free_nodes);
+    return 0;
+}
diff --git a/src/tasks/task07_free_insert.c b/src/tasks/task07_free_insert.c
new file mode 100644
index 0000000..be428a8
--- /dev/null
+++ b/src/tasks/task07_free_insert.c
@@ -0,0 +1,88 @@
+#include "heap4_common.h"
+
+static uint8_t heap_area[192];
+static HeapBlock start;
+static HeapBlock *end_marker;
+
+volatile int g_order_ok;
+volatile int g_free_count;
+volatile size_t g_total_free;
+
+static void insert_block(HeapBlock *block)
+{
+    HeapBlock *iterator;
+
+    for (iterator = &start; iterator->next < block; iterator = iterator->next)
+        ;
+
+    block->next = iterator->next;
+    iterator->next = block;
+}
+
+static void heap_free_model(void *p)
+{
+    HeapBlock *block;
+
+    if (p == 0)
+        return;
+
+    block = (HeapBlock *)((uint8_t *)p - sizeof(HeapBlock));
+    block->size = heap4_clear_allocated(block->size);
+    insert_block(block);
+}
+
+static int count_free(void)
+{
+    HeapBlock *block;
+    int count;
+
+    count = 0;
+    for (block = start.next; block != end_marker; block = block->next)
+        count++;
+    return count;
+}
+
+static size_t total_free(void)
+{
+    HeapBlock *block;
+    size_t total;
+
+    total = 0U;
+    for (block = start.next; block != end_marker; block = block->next)
+        total += block->size;
+    return total;
+}
+
+int main(void)
+{
+    HeapBlock *a;
+    HeapBlock *b;
+    HeapBlock *c;
+    void *payload;
+
+    a = (HeapBlock *)&heap_area[0];
+    b = (HeapBlock *)&heap_area[64];
+    c = (HeapBlock *)&heap_area[128];
+    end_marker = (HeapBlock *)&heap_area[176];
+
+    start.next = a;
+    a->next = c;
+    c->next = end_marker;
+    end_marker->next = 0;
+
+    a->size = 40U;
+    b->size = heap4_mark_allocated(32U);
+    c->size = 48U;
+    end_marker->size = 0U;
+
+    payload = (uint8_t *)b + sizeof(HeapBlock);
+    heap_free_model(payload);
+
+    g_order_ok = start.next == a && a->next == b && b->next == c && c->next == end_marker;
+    g_free_count = count_free();
+    g_total_free = total_free();
+
+    TRACE_PRINTF("order=%d count=%d total=%u\n",
+                 g_order_ok, g_free_count, (unsigned)g_total_free);
+    return 0;
+}
diff --git a/src/tasks/task08_coalescing.c b/src/tasks/task08_coalescing.c
new file mode 100644
index 0000000..02b3f48
--- /dev/null
+++ b/src/tasks/task08_coalescing.c
@@ -0,0 +1,76 @@
+#include "heap4_common.h"
+
+static uint8_t heap_area[192];
+static HeapBlock start;
+static HeapBlock *end_marker;
+
+volatile int g_free_count;
+volatile size_t g_merged_size;
+volatile int g_merged_with_right;
+
+static void insert_block_merge(HeapBlock *block)
+{
+    HeapBlock *iterator;
+    uint8_t *block_end;
+
+    for (iterator = &start; iterator->next < block; iterator = iterator->next)
+        ;
+
+    block_end = (uint8_t *)block + block->size;
+    if (block_end == (uint8_t *)iterator->next) {
+        block->size += iterator->next->size;
+        block->next = iterator->next->next;
+    } else {
+        block->next = iterator->next;
+    }
+
+    if (iterator != &start && heap4_blocks_touch(iterator, block)) {
+        iterator->size += block->size;
+        iterator->next = block->next;
+    } else {
+        iterator->next = block;
+    }
+}
+
+static int count_free(void)
+{
+    HeapBlock *block;
+    int count;
+
+    count = 0;
+    for (block = start.next; block != end_marker; block = block->next)
+        count++;
+    return count;
+}
+
+int main(void)
+{
+    HeapBlock *left;
+    HeapBlock *middle;
+    HeapBlock *right;
+
+    left = (HeapBlock *)&heap_area[0];
+    middle = (HeapBlock *)&heap_area[48];
+    right = (HeapBlock *)&heap_area[96];
+    end_marker = (HeapBlock *)&heap_area[160];
+
+    start.next = left;
+    left->next = right;
+    right->next = end_marker;
+    end_marker->next = 0;
+
+    left->size = 48U;
+    middle->size = 48U;
+    right->size = 64U;
+    end_marker->size = 0U;
+
+    insert_block_merge(middle);
+
+    g_free_count = count_free();
+    g_merged_size = start.next->size;
+    g_merged_with_right = start.next->next == end_marker;
+
+    TRACE_PRINTF("count=%d size=%u merged_right=%d\n",
+                 g_free_count, (unsigned)g_merged_size, g_merged_with_right);
+    return 0;
+}
diff --git a/src/tasks/task09_config_macros.c b/src/tasks/task09_config_macros.c
new file mode 100644
index 0000000..cc64b13
--- /dev/null
+++ b/src/tasks/task09_config_macros.c
@@ -0,0 +1,34 @@
+#include "heap4_common.h"
+
+#ifndef CONFIG_TOTAL_HEAP_SIZE
+#define CONFIG_TOTAL_HEAP_SIZE 256U
+#endif
+
+#ifndef CONFIG_SUPPORT_DYNAMIC_ALLOCATION
+#define CONFIG_SUPPORT_DYNAMIC_ALLOCATION 1
+#endif
+
+#define CONFIG_ADJUSTED_HEAP_SIZE (CONFIG_TOTAL_HEAP_SIZE - HEAP4_ALIGNMENT)
+
+volatile size_t g_total_heap;
+volatile size_t g_adjusted_heap;
+volatile int g_dynamic_enabled;
+volatile int g_trace_is_host_only;
+
+int main(void)
+{
+    g_total_heap = CONFIG_TOTAL_HEAP_SIZE;
+    g_adjusted_heap = CONFIG_ADJUSTED_HEAP_SIZE;
+    g_dynamic_enabled = CONFIG_SUPPORT_DYNAMIC_ALLOCATION;
+
+#ifdef HOST_PRINTF
+    g_trace_is_host_only = 1;
+#else
+    g_trace_is_host_only = 0;
+#endif
+
+    TRACE_PRINTF("heap=%u adjusted=%u dynamic=%d host_trace=%d\n",
+                 (unsigned)g_total_heap, (unsigned)g_adjusted_heap,
+                 g_dynamic_enabled, g_trace_is_host_only);
+    return 0;
+}
diff --git a/src/tasks/task10_heap4_demo.c b/src/tasks/task10_heap4_demo.c
new file mode 100644
index 0000000..f16b408
--- /dev/null
+++ b/src/tasks/task10_heap4_demo.c
@@ -0,0 +1,175 @@
+#include "heap4_common.h"
+
+#define HEAP_BYTES 256U
+#define MIN_SPLIT_SIZE ((size_t)(sizeof(HeapBlock) * 2U))
+
+static uint8_t heap_area[HEAP_BYTES + HEAP4_ALIGNMENT];
+static HeapBlock start;
+static HeapBlock *end_marker;
+
+volatile int g_allocations_ok;
+volatile int g_final_free_nodes;
+volatile size_t g_final_free_total;
+volatile size_t g_minimum_ever_free;
+
+static size_t free_bytes_remaining;
+static size_t minimum_ever_free;
+
+static size_t list_total(void)
+{
+    HeapBlock *block;
+    size_t total;
+
+    total = 0U;
+    for (block = start.next; block != end_marker; block = block->next)
+        total += block->size;
+    return total;
+}
+
+static int list_count(void)
+{
+    HeapBlock *block;
+    int count;
+
+    count = 0;
+    for (block = start.next; block != end_marker; block = block->next)
+        count++;
+    return count;
+}
+
+static void insert_block_merge(HeapBlock *block)
+{
+    HeapBlock *iterator;
+    uint8_t *block_end;
+
+    for (iterator = &start; iterator->next < block; iterator = iterator->next)
+        ;
+
+    block_end = (uint8_t *)block + block->size;
+    if (block_end == (uint8_t *)iterator->next) {
+        block->size += iterator->next->size;
+        block->next = iterator->next->next;
+    } else {
+        block->next = iterator->next;
+    }
+
+    if (iterator != &start && heap4_blocks_touch(iterator, block)) {
+        iterator->size += block->size;
+        iterator->next = block->next;
+    } else {
+        iterator->next = block;
+    }
+}
+
+static void heap_init(void)
+{
+    uintptr_t raw;
+    uintptr_t aligned;
+    size_t available;
+    HeapBlock *first;
+
+    raw = (uintptr_t)&heap_area[0];
+    aligned = heap4_align_address(raw);
+    available = HEAP_BYTES - (size_t)(aligned - raw);
+    available &= ~HEAP4_ALIGNMENT_MASK;
+
+    first = (HeapBlock *)aligned;
+    end_marker = (HeapBlock *)(aligned + available - sizeof(HeapBlock));
+    end_marker->next = 0;
+    end_marker->size = 0U;
+
+    first->next = end_marker;
+    first->size = (uint8_t *)end_marker - (uint8_t *)first;
+    start.next = first;
+    start.size = 0U;
+
+    free_bytes_remaining = first->size;
+    minimum_ever_free = free_bytes_remaining;
+}
+
+static void *heap_malloc_model(size_t wanted)
+{
+    HeapBlock *previous;
+    HeapBlock *block;
+    HeapBlock *remainder;
+    size_t total;
+    size_t original;
+
+    if (wanted == 0U)
+        return 0;
+
+    total = heap4_align_up(wanted + sizeof(HeapBlock));
+    previous = &start;
+    block = start.next;
+
+    while (block != end_marker) {
+        if (block->size >= total) {
+            original = block->size;
+            if (original - total > MIN_SPLIT_SIZE) {
+                remainder = (HeapBlock *)((uint8_t *)block + total);
+                remainder->size = original - total;
+                remainder->next = block->next;
+                previous->next = remainder;
+                block->size = total;
+            } else {
+                previous->next = block->next;
+                total = original;
+            }
+
+            block->next = 0;
+            block->size = heap4_mark_allocated(block->size);
+            free_bytes_remaining -= total;
+            if (free_bytes_remaining < minimum_ever_free)
+                minimum_ever_free = free_bytes_remaining;
+            return (uint8_t *)block + sizeof(HeapBlock);
+        }
+        previous = block;
+        block = block->next;
+    }
+
+    return 0;
+}
+
+static void heap_free_model(void *p)
+{
+    HeapBlock *block;
+    size_t size;
+
+    if (p == 0)
+        return;
+
+    block = (HeapBlock *)((uint8_t *)p - sizeof(HeapBlock));
+    if (!heap4_is_allocated(block->size))
+        return;
+
+    size = heap4_clear_allocated(block->size);
+    block->size = size;
+    free_bytes_remaining += size;
+    insert_block_merge(block);
+}
+
+int main(void)
+{
+    void *a;
+    void *b;
+    void *c;
+
+    heap_init();
+
+    a = heap_malloc_model(24U);
+    b = heap_malloc_model(40U);
+    heap_free_model(a);
+    c = heap_malloc_model(16U);
+    heap_free_model(b);
+    heap_free_model(c);
+
+    g_allocations_ok = a != 0 && b != 0 && c != 0;
+    g_final_free_nodes = list_count();
+    g_final_free_total = list_total();
+    g_minimum_ever_free = minimum_ever_free;
+
+    TRACE_PRINTF("ok=%d nodes=%d free=%u min=%u\n",
+                 g_allocations_ok, g_final_free_nodes,
+                 (unsigned)g_final_free_total, (unsigned)g_minimum_ever_free);
+    return 0;
+}