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#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
; void *memcpy(void *dest, const void *src, size_t len)
.text
.global _U(memcpy)
.type _U(memcpy), @function
_U(memcpy):
LOAD_Z(src_lo, src_hi)
LOAD_X(dest_lo, dest_hi)
#if OPTIMIZE_SPEED
; 15 words, (14 + len * 6 - (len & 1)) cycles
sbrs len_lo, 0
rjmp .memcpy_start
rjmp .memcpy_odd
.memcpy_loop:
ld __tmp_reg__, Z+
st X+, __tmp_reg__
.memcpy_odd:
ld __tmp_reg__, Z+
st X+, __tmp_reg__
.memcpy_start:
subi len_lo, lo8(2)
sbci len_hi, hi8(2)
#else
; 11 words, (13 + len * 8) cycles
rjmp .memcpy_start
.memcpy_loop:
ld __tmp_reg__, Z+
st X+, __tmp_reg__
.memcpy_start:
subi len_lo, lo8(1)
sbci len_hi, hi8(1)
#endif
brcc .memcpy_loop
; return dest (unchanged)
ret
.memcpy_end:
.size _U(memcpy), .memcpy_end - _U(memcpy)
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