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nub31
2025-02-04 11:47:25 +01:00
parent 36cc302d99
commit 774dcfa995
4 changed files with 407 additions and 43 deletions
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130
input/baseline/gc.asm
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@@ -1,13 +1,19 @@
global gc_init, gc_alloc
extern alloc, free
extern alloc, free, printint, printstr, endl
section .bss
alloc_list: resq 1 ; head of alloc list
stack_start: resq 1 ; start of stack
alloc_list_head: resq 1
free_list_head: resq 1
stack_start: resq 1
section .data
gc_threshold_c: dq 1024 ; default of 1024 allocations
total_alloc_c: dq 0 ; count the amount of allocations
gc_bytes_allocated: dq 0 ; bytes allocated since the last gc cycle
gc_trigger_threshold: dq 1024 * 1024 * 8 ; initial gc trigger threshold in bytes (adjusts dynamically)
gc_start_text: db "Running gc after ", 0
gc_sweep_done_text: db " Sweep done. We no have ", 0
gc_next_threshold: db " The next threshold is ", 0
gc_allocated_bytes: db " allocated bytes", 0
gc_mark_done_text: db " Marking done", 0
section .text
gc_init:
@@ -15,30 +21,65 @@ gc_init:
ret
gc_alloc:
add rdi, 24 ; add space for metadata
mov rdx, [total_alloc_c] ; load total allocation count
cmp rdx, [gc_threshold_c] ; has count exceeded threshold?
jb .skip_collect ; yes? run gc
add rdi, 24
mov rdx, [gc_bytes_allocated]
cmp rdx, [gc_trigger_threshold]
jb .skip_collect ; if allocated bytes since last collect has exceeded threshold, trigger collect
push rdi
call gc_collect
pop rdi
.skip_collect:
inc qword [total_alloc_c] ; update total allocation count
add [gc_bytes_allocated], rdi
push rdi
call alloc ; 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)
mov rsi, [alloc_list] ; load first item in allocation list
mov qword [rax + 16], rsi ; make current head of allocation list the next item in this object
mov [alloc_list], rax ; update head of allocation list so it points to this object
add rax, 24 ; skip metadata for return value
mov byte [rax], 0 ; set mark to 0
mov qword [rax + 8], rdi ; set total size of object (including metadata)
mov rsi, [alloc_list_head] ; load first item in allocation list
mov qword [rax + 16], rsi ; make current head of allocation list the next item in this object
mov [alloc_list_head], rax ; update head of allocation list so it points to this object
add rax, 24 ; skip metadata for return value
ret
gc_collect:
mov rdi, gc_start_text
call printstr
mov rdi, [gc_bytes_allocated]
call printint
mov rdi, gc_allocated_bytes
call printstr
call endl
call gc_mark_stack
mov rdi, gc_mark_done_text
call printstr
call endl
call gc_sweep
mov qword [total_alloc_c], 0 ; reset allocation count
mov rdi, gc_sweep_done_text
call printstr
mov rdi, [gc_bytes_allocated]
call printint
mov rdi, gc_allocated_bytes
call printstr
call endl
mov rdi, [gc_bytes_allocated]
shl rdi, 1
mov rsi, 1024 * 1024 * 8
call max
mov [gc_trigger_threshold], rax
mov qword [gc_bytes_allocated], 0
mov rdi, gc_next_threshold
call printstr
mov rdi, [gc_trigger_threshold]
call printint
mov rdi, gc_allocated_bytes
call printstr
call endl
ret
gc_mark_stack:
@@ -57,7 +98,7 @@ gc_mark_stack:
gc_mark:
test rdi, rdi ; is input null?
jz .done ; yes? return
mov rsi, [alloc_list] ; load start of allocation list
mov rsi, [alloc_list_head] ; load start of allocation list
.loop:
test rsi, rsi ; reached end of list?
jz .done ; yes? return
@@ -85,32 +126,43 @@ gc_mark:
ret
gc_sweep:
mov rdi, [alloc_list]
mov rdi, [alloc_list_head]
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 .unmarked ; 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
.free:
mov rdx, [rdi + 16] ; save address of next object in list
mov rdi, [rdi + 16] ; load the next object in the list
jmp .loop ; repeat
.unmarked:
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
jmp .free_memory
mov [rsi + 16], rdx ; unlink the current node by setting the previous node's next to the next node's address
jmp .free
.remove_head:
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
call free ; free the memory
pop rdi ; input for next iteration
pop rsi ; prev node for next iteration
mov [alloc_list_head], rdx ; update head node to be the next node
.free:
push rsi ; save previous node since it will also be the previous node for the next item
push rdx ; save next node
mov rdx, [rdi + 8] ; load the size of the object
sub [gc_bytes_allocated], rdx ; adjust allocated bytes
call free ; free the memory
pop rdi ; input for next iteration
pop rsi ; prev node for next iteration
jmp .loop
.done:
ret
ret
max:
cmp rdi, rsi
jae .left
mov rax, rsi
ret
.left:
mov rax, rdi
ret