From 3132790ab5a3450bdc064ec7de9ec42f2e0e3c8a Mon Sep 17 00:00:00 2001
From: jespergravgaard <jesper@balmangravgaard.dk>
Date: Tue, 21 May 2019 00:33:36 +0200
Subject: [PATCH] Added very naive heap implementation.

---
 .../dk/camelot64/kickc/test/TestPrograms.java |  5 ++
 src/test/kc/memory-heap.kc                    | 34 ++++++++++
 src/test/ref/memory-heap.asm                  | 66 +++++++++++++++++++
 3 files changed, 105 insertions(+)
 create mode 100644 src/test/kc/memory-heap.kc
 create mode 100644 src/test/ref/memory-heap.asm

diff --git a/src/test/java/dk/camelot64/kickc/test/TestPrograms.java b/src/test/java/dk/camelot64/kickc/test/TestPrograms.java
index 39ac64c0b..4a2357ddc 100644
--- a/src/test/java/dk/camelot64/kickc/test/TestPrograms.java
+++ b/src/test/java/dk/camelot64/kickc/test/TestPrograms.java
@@ -68,6 +68,11 @@ public class TestPrograms {
       compileAndCompare("hex2dec");
    }
 
+   @Test
+   public void testMemoryHeap() throws IOException, URISyntaxException {
+      compileAndCompare("memory-heap");
+   }
+
    @Test
    public void testTernaryInference() throws IOException, URISyntaxException {
       compileAndCompare("ternary-inference");
diff --git a/src/test/kc/memory-heap.kc b/src/test/kc/memory-heap.kc
new file mode 100644
index 000000000..2fa915342
--- /dev/null
+++ b/src/test/kc/memory-heap.kc
@@ -0,0 +1,34 @@
+// Experiments with malloc()
+
+void main() {
+    unsigned char* buf1 = (unsigned char*) malloc(100);
+    unsigned char* buf2 = (unsigned char*) malloc(100);
+    for(unsigned char i:0..99) {
+        buf1[i] = i;
+        buf2[i] = 255-i;
+    }
+    free(buf1);
+    free(buf2);
+    unsigned char* screen = 0x0400;
+    screen[0] = *buf1;
+    screen[1] = *buf2;
+}
+
+// Start of the heap used by malloc()
+unsigned char* HEAP_START = 0xc000;
+
+// Head of the heap. Moved forward for each malloc()
+unsigned char* heap_head = HEAP_START;
+
+// Allocates a block of size bytes of memory, returning a pointer to the beginning of the block.
+// The content of the newly allocated block of memory is not initialized, remaining with indeterminate values.
+unsigned char* malloc(unsigned int size) {
+    unsigned char* mem = heap_head;
+    heap_head+= size;
+    return mem;
+}
+
+// A block of memory previously allocated by a call to malloc is deallocated, making it available again for further allocations.
+// If ptr is a null pointer, the function does nothing.
+void free(unsigned char* ptr) {
+}
\ No newline at end of file
diff --git a/src/test/ref/memory-heap.asm b/src/test/ref/memory-heap.asm
new file mode 100644
index 000000000..769942503
--- /dev/null
+++ b/src/test/ref/memory-heap.asm
@@ -0,0 +1,66 @@
+// Experiments with malloc()
+.pc = $801 "Basic"
+:BasicUpstart(main)
+.pc = $80d "Program"
+  // Start of the heap used by malloc()
+  .label HEAP_START = $c000
+  .label heap_head = 2
+main: {
+    .label screen = $400
+    .label buf1 = 4
+    .label buf2 = 6
+    lda #<HEAP_START
+    sta heap_head
+    lda #>HEAP_START
+    sta heap_head+1
+    jsr malloc
+    lda malloc.return_2
+    sta malloc.return
+    lda malloc.return_2+1
+    sta malloc.return+1
+    jsr malloc
+    ldy #0
+  b1:
+    tya
+    sta (buf1),y
+    tya
+    eor #$ff
+    clc
+    adc #$ff+1
+    sta (buf2),y
+    iny
+    cpy #$64
+    bne b1
+    jsr free
+    jsr free
+    ldy #0
+    lda (buf1),y
+    sta screen
+    lda (buf2),y
+    sta screen+1
+    rts
+}
+// A block of memory previously allocated by a call to malloc is deallocated, making it available again for further allocations.
+// If ptr is a null pointer, the function does nothing.
+free: {
+    rts
+}
+// Allocates a block of size bytes of memory, returning a pointer to the beginning of the block.
+// The content of the newly allocated block of memory is not initialized, remaining with indeterminate values.
+malloc: {
+    .label return = 4
+    .label return_1 = 6
+    .label return_2 = 6
+    lda heap_head
+    sta return_2
+    lda heap_head+1
+    sta return_2+1
+    lda #$64
+    clc
+    adc heap_head
+    sta heap_head
+    bcc !+
+    inc heap_head+1
+  !:
+    rts
+}