1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
;
; 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
|
