mirror of
https://github.com/cc65/cc65.git
synced 2024-11-10 10:04:50 +00:00
86 lines
1.9 KiB
ArmAsm
86 lines
1.9 KiB
ArmAsm
;
|
|
; Ullrich von Bassewitz, 18.07.2000
|
|
;
|
|
; char* __fastcall__ strdup (const char* S);
|
|
;
|
|
; Note: The code knowns which zero page locations are used by malloc.
|
|
;
|
|
|
|
.importzp sp, tmp1, ptr4
|
|
.import pushax, decsp4, incsp4
|
|
.import _strlen, _malloc, _memcpy
|
|
.export _strdup
|
|
|
|
.macpack cpu
|
|
.macpack generic
|
|
|
|
_strdup:
|
|
|
|
; Since we need some place to store the intermediate results, allocate a
|
|
; stack frame. To make this somewhat more efficient, create the stackframe
|
|
; as needed for the final call to the memcpy function.
|
|
|
|
pha ; decsp will destroy A (but not X)
|
|
jsr decsp4 ; Target/source
|
|
|
|
; Store the pointer into the source slot
|
|
|
|
ldy #1
|
|
txa
|
|
sta (sp),y
|
|
pla
|
|
.if (.cpu .bitand CPU_ISET_65SC02)
|
|
sta (sp)
|
|
.else
|
|
dey
|
|
sta (sp),y
|
|
.endif
|
|
|
|
; Get length of S (which is still in a/x)
|
|
|
|
jsr _strlen
|
|
|
|
; Calculate strlen(S)+1 (the space needed)
|
|
|
|
add #1
|
|
bcc @L1
|
|
inx
|
|
|
|
; Save the space we're about to allocate in ptr4
|
|
|
|
@L1: sta ptr4
|
|
stx ptr4+1
|
|
|
|
; Allocate memory. _malloc will not use ptr4
|
|
|
|
jsr _malloc
|
|
|
|
; Store the result into the target stack slot
|
|
|
|
ldy #2
|
|
sta (sp),y ; Store low byte
|
|
sta tmp1
|
|
txa ; Get high byte
|
|
iny
|
|
sta (sp),y ; Store high byte
|
|
|
|
; Check for a NULL pointer
|
|
|
|
ora tmp1
|
|
beq OutOfMemory
|
|
|
|
; Copy the string. memcpy will return the target string which is exactly
|
|
; what we need here. It will also drop the allocated stack frame.
|
|
|
|
lda ptr4
|
|
ldx ptr4+1 ; Load size
|
|
jmp _memcpy ; Copy string, drop stackframe
|
|
|
|
; Out of memory, return NULL (A = 0)
|
|
|
|
OutOfMemory:
|
|
tax
|
|
jmp incsp4 ; Drop stack frame
|
|
|
|
|