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
|
#include "macros.inc"
#define dest_hi r25
#define dest_lo r24
#define src_hi r23
#define src_lo r22
#define len_hi r21
#define len_lo r20
; char *strncpy_P(char *dest, const char flash *src, size_t len)
.text
.global _U(strncpy_P)
.type _U(strncpy_P), @function
_U(strncpy_P):
LOAD_Z(src_lo, src_hi)
LOAD_X(dest_lo, dest_hi)
.strncpy_P_loop:
subi len_lo, lo8(1)
sbci len_hi, hi8(1)
brcs .strncpy_P_done
LPM_R0_ZP
st X+, r0
tst r0
brne .strncpy_P_loop
; store null characters up to the end of dest
; as the glibc manual says:
; This behavior is rarely useful, but it is specified by the ISO C standard.
rjmp .strncpy_P_clr_start
.strncpy_P_clr_loop:
st X+, __zero_reg__
.strncpy_P_clr_start:
subi len_lo, lo8(1)
sbci len_hi, hi8(1)
brcc .strncpy_P_clr_loop
.strncpy_P_done:
; return dest (unchanged)
ret
.strncpy_P_end:
.size _U(strncpy_P), .strncpy_P_end - _U(strncpy_P)
|
