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cc65/libsrc/common/calloc.s

64 lines
1.2 KiB
ArmAsm

;
; Ullrich von Bassewitz, 15.11.2001
;
; Allocate a block and zero it.
;
; void* __fastcall__ calloc (size_t count, size_t size);
;
.export _calloc
.import _malloc, __bzero
.import tosumulax, pushax
; -------------------------------------------------------------------------
.proc _calloc
; We have the first argument in a/x and the second on the stack. Calling
; tosumulax will give the product of both in a/x.
jsr tosumulax
; Save size for later
sta Size
stx Size+1
; malloc() is a fastcall function, so we do already have the argument in
; the right place
jsr _malloc
; Check for a NULL pointer
cpx #0
bne ClearBlock
cmp #0
bne ClearBlock
; We have a NULL pointer, bail out
rts
; No NULL pointer, clear the block. _bzero will return a pointer to the
; block which is exactly what we want.
ClearBlock:
jsr pushax ; ptr
lda Size
ldx Size+1 ; Size
jmp __bzero
.endproc
; -------------------------------------------------------------------------
; Data
.bss
Size: .res 2