1 files changed, 244 insertions, 0 deletions
diff --git a/test/masm/test.asm b/test/masm/test.asm
new file mode 100644
index 0000000..d70f3e7
--- /dev/null
+++ b/test/masm/test.asm
@@ -0,0 +1,244 @@
+# Copyright (c) 2024 Freya Murphy
+
+.data
+.align 2
+
+heap_start:
+	.space 4
+heap_len:
+	.space 4
+heap_free:
+	.space 4
+heap_ptr:
+	.space 4
+
+null:
+	.space 4
+
+.text
+.align 2
+.globl main
+.globl _start
+
+# init the heap
+heap_init:
+	# sbrk(0)
+	li	$v0, 9
+	li	$a0, 0
+	syscall
+	sw	$v0, heap_start
+	sw	$v1, heap_len
+
+	# heap is empty, ptr at start
+	sw	$v0, heap_ptr
+	# heap is empty, size = len
+	sw	$v1, heap_free
+
+	jr	$ra
+
+
+
+# $a0 : amount of bytes to increase
+heap_increase:
+	# t0 : OLD heap len + 1
+	# t1 : heap ptr
+	# t2 : heap end
+	# t2 : heap free
+	# t3 : a0
+
+	# save current length
+	lw	$t0, heap_len
+
+	# save a0
+	move	$t3, $a0
+
+	# sbrk(amt)
+	li	$v0, 9
+	syscall
+	# sbrk(0)
+	li	$v0, 9
+	li	$a0, 0
+	syscall
+	sw	$v0, heap_start
+	sw	$v1, heap_len
+
+	lw	$t1, heap_ptr    # heap ptr
+	add	$t2, $v0, $v1   # heap end
+	sub	$t3, $t2, $t1   # heap free
+	sw	$t3, heap_free
+
+	# set return code to 1 if fail to allocate
+	# i.e. $v1 = $t0 or ($v1 < $t0 + 1)
+	# i.e. heap size hasen't changed
+	addi	$t0, $t0, 1
+	slt	$v0, $v1, $t0
+	jr	$ra
+
+
+
+# $a0 : amount of bytes to allocate
+malloc:
+	# t0 : heap free + 1
+	# t1 : if enough mem is free
+	# t2 : alloc size [(a0 align 4) + 4096 + 4]
+	# t3 : temp for heap_ptr
+	# t7 : alloc amt (a0 align 4) + 4
+	# t8 : temp for modulo
+
+	# save $a0
+	move	$t7, $a0
+	addi	$t7, $t7, 4 # add 4 bytes to save INTERAL ptr size
+
+	# align $t7 by 4
+	# allows us to use lw and sw in realloc
+	li	$t8, 4
+	div	$t8, $t7, $t8
+	mfhi	$t8
+	beq	$t8, $zero, malloc_aligned
+	addi	$t7, $t7, 4
+	sub	$t7, $t7, $t8
+
+malloc_aligned:
+	# check if we have enough memory free
+	lw	$t0, heap_free
+	addi	$t0, $t0, 1
+	slt	$t1, $t7, $t0
+	bne	$t1, $zero, malloc_hasmem
+
+	# set needed mem to alloc
+	# page size + alloc request
+
+	# save $ra and $t7
+	addi	$sp, $sp, -8
+	sw	$ra, 0($sp)
+	sw	$t7, 4($sp)
+
+	li	$t2, 4096
+	add	$t2, $t2, $t7
+	move	$a0, $t2
+	jal	heap_increase
+
+	# pop $ra and $t7
+	lw	$ra, 0($sp)
+	lw	$t7, 4($sp)
+	addi	$sp, $sp, 8
+
+	# check heap_increase return code
+	beq	$v0, $zero, malloc_hasmem
+
+malloc_error:
+	# failed to sbrk, return null
+	la	$v0, null
+	jr	$ra
+
+malloc_hasmem:
+	# set return value, and save ptr size in it
+	# add 4 to return ptr, since first 4 bytes are INTERNAL
+	addi	$t3, $t7, -4
+	lw	$v0, heap_ptr
+	sw	$t3, ($v0)
+	addi	$v0, $v0, 4
+
+	lw	$t3, heap_ptr
+	add	$t3, $t3, $t7 # increase ptr by alloc size
+	sw	$t3, heap_ptr
+
+	jr	$ra
+
+
+
+# $a0 : address of ptr
+free:
+	# haha hehe hoho
+	jr	$ra
+
+
+
+# $a0 : new size
+# $a1 : old ptr
+realloc:
+	# t0 : old ptr size
+	# t2 : new ptr addr
+
+	# check if $a0 is zero, if so then just free
+	bne	$a0, $zero, realloc_inner
+	move	$a0, $a1
+	la	$v0, null
+	j	free
+
+	# save to stack
+	addi	$sp, $sp, -12
+	sw	$ra, 0($sp)
+	sw	$a0, 4($sp)
+	sw	$a1, 8($sp)
+
+	jal	malloc
+
+	# pop to stack
+	lw	$ra, 0($sp)
+	lw	$a0, 4($sp)
+	lw	$a1, 8($sp)
+	addi	$sp, $sp, 12
+
+realloc_inner:
+	addi	$a1, $a1, -4
+	lw	$t0, ($a1)
+	addi	$a1, $a1, 4
+
+realloc_loop:
+	# loop until $t0 or $t1 is zero
+	beq	$t0, $zero, realloc_end
+	beq	$a0, $zero, realloc_end
+
+	addi	$a1, $a1, 4
+	addi	$t0, $t0, -4
+	addi	$a0, $a0, -4
+	#lw	$t3,
+
+	j	realloc_loop
+
+realloc_end:
+
+
+realloc_free:
+	jr	$ra
+
+
+_start:
+main:
+	# push return address
+	addi	$sp, $sp, -4
+	sw	$ra, ($sp)
+
+	jal	heap_init
+
+	li	$a0, 24
+	jal	malloc
+
+	move	$a0, $v0
+	li	$v0, 1
+	syscall
+
+	li	$v0, 11
+	li	$a0, 10
+	syscall
+
+	li	$a0, 24
+	jal	malloc
+
+	move	$a0, $v0
+	li	$v0, 1
+	syscall
+
+	li	$v0, 11
+	li	$a0, 10
+	syscall
+
+	# pop return address
+	lw	$ra, ($sp)
+	addi	$sp, $sp, 4
+
+exit:
+	# exit with code 0
+	li	$v0, 0
+	jr	$ra