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update gc to use alloc. Still buggy

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nub31
2025-02-03 23:02:05 +01:00
parent 535444eb2a
commit 36cc302d99
1 changed files with 24 additions and 75 deletions
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99
input/baseline/gc.asm
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@@ -1,13 +1,12 @@
global gc_init, gc_alloc
extern alloc, free
section .bss
alloc_list: resq 1 ; head of alloc list
stack_start: resq 1 ; start of stack
section .data
gc_threshold_b: dq 4096 ; default of 4096 bytes, this will scale when gc_collect is ran
gc_threshold_c: dq 1024 ; default of 1024 allocations
total_alloc_b: dq 0 ; counts the allocated bytes
gc_threshold_c: dq 1024 ; default of 1024 allocations
total_alloc_c: dq 0 ; count the amount of allocations
section .text
@@ -17,22 +16,16 @@ gc_init:
gc_alloc:
add rdi, 24 ; add space for metadata
mov rdx, [total_alloc_b] ; load total allocations in bytes
cmp rdx, [gc_threshold_b] ; has total exceeded threshold?
jae .collect ; yes? run gc
mov rdx, [total_alloc_c] ; load total allocation count
cmp rdx, [gc_threshold_c] ; has count exceeded threshold?
jae .collect ; yes? run gc
jmp .collect_end
.collect:
jb .skip_collect ; yes? run gc
push rdi
call gc_collect
pop rdi
.collect_end:
add [total_alloc_b], rdi ; update total allocated bytes
.skip_collect:
inc qword [total_alloc_c] ; update total allocation count
push rdi
call sys_mmap ; allocate size + metadata
call alloc ; allocate size + metadata
pop rdi
mov byte [rax], 0 ; set mark to 0
mov qword [rax + 8], rdi ; set total size of object (including metadata)
@@ -45,12 +38,7 @@ gc_alloc:
gc_collect:
call gc_mark_stack
call gc_sweep
mov qword [total_alloc_c], 0 ; reset allocation count
mov rdi, [total_alloc_b] ; since we just swept, all the memory is in use
shl rdi, 1 ; double the currently used memory
mov rsi, 4096
call max ; get the largest of total_alloc_b * 2 and 4096
mov qword [gc_threshold_b], rax ; update threshold to new value
mov qword [total_alloc_c], 0 ; reset allocation count
ret
gc_mark_stack:
@@ -58,10 +46,10 @@ gc_mark_stack:
mov r9, [stack_start] ; load start of stack
.loop:
cmp r8, r9 ; have we reached end of stack?
ja .done ; yes? return
jae .done ; yes? return
mov rdi, [r8] ; no? load the value
call gc_mark ; this might be an allocation, check
add r8, 8 ; next item in stack
lea r8, [r8 + 8] ; next item in stack
jmp .loop
.done:
ret
@@ -100,68 +88,29 @@ gc_sweep:
mov rdi, [alloc_list]
xor rsi, rsi
.loop:
test rdi, rdi ; reached end of list?
jz .done ; yes? return
test rdi, rdi ; reached end of list?
jz .done ; yes? return
mov al, [rdi]
test al, al ; is object marked?
jz .free ; no? free it
mov byte [rdi], 0 ; yes? clear mark for next marking
test al, al ; is object marked?
jz .free ; no? free it
mov byte [rdi], 0 ; yes? clear mark for next marking
mov rsi, rdi
mov rdi, [rdi + 16] ; load the next object in the list
jmp .loop ; repeat
mov rdi, [rdi + 16] ; load the next object in the list
jmp .loop ; repeat
.free:
mov rdx, [rdi + 16] ; save address of next object in list
mov rdx, [rdi + 16] ; save address of next object in list
test rsi, rsi
jz .remove_head
mov [rsi + 16], rdx ; unlink the current node by setting the previous node's next to the next node's address
mov [rsi + 16], rdx ; unlink the current node by setting the previous node's next to the next node's address
jmp .free_memory
.remove_head:
mov [alloc_list], rdx ; update head node to be the next node
mov [alloc_list], rdx ; update head node to be the next node
.free_memory:
push rsi ; save previous node since it will also be the previous node for the next item
push rdx ; save next node
mov rsi, [rdi + 8] ; get length of the object
sub [total_alloc_b], rsi ; remove this allocation from total allocations
call sys_munmap ; free the memory
pop rdi ; input for next iteration
pop rsi ; prev node for next iteration
push rsi ; save previous node since it will also be the previous node for the next item
push rdx ; save next node
call free ; free the memory
pop rdi ; input for next iteration
pop rsi ; prev node for next iteration
jmp .loop
.done:
ret
sys_mmap:
mov rax, 9
mov rsi, rdi
mov rdi, 0
mov rdx, 3
mov r10, 34
mov r8, -1
mov r9, 0
syscall
cmp rax, -1
je .error
ret
.error:
mov rax, 60
mov rdi, 1
syscall
sys_munmap:
mov rax, 11
syscall
cmp rax, -1
je .error
ret
.error:
mov rax, 60
mov rdi, 1
syscall
max:
cmp rdi, rsi
jae .left
mov rax, rsi
ret
.left:
mov rax, rdi
ret
ret