toolchain/src/libc/memcpy.src at d56bedb787808d766ad7f535e0eda645b4e0d1b1 · CE-Programming/toolchain · GitHub

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	.assume	adl=1

	.section	.text

	.global	_memcpy
	.type	_memcpy, @function

	; Note: TiOS memcpy works fine, but our implementation is faster
	; .set	_memcpy, 0x0000A4

_memcpy:
	; size >  0     : 25F + 15R + 1 + LDIR
	; size >= 65536 : 32F + 16R + 3 + LDIR (only when the low 16 bits are zero)
	; size == 0     : 26F + 13R + 2

	ld	iy, 0
	add	iy, sp
	ld	bc, (iy + 9)	; Load count
	ld	a, c
	or	a, b
	ld	de, (iy + 3)	; Load destination
	jr	z, .L.maybe_zero
.L.not_zero:
	ld	hl, (iy + 6)	; Load source
	ldir
	ld	hl, (iy + 3)	; Return the destination pointer
	ret

.L.maybe_zero:
	; low 16 bits are zero
	or	a, (iy + 11)	; test upper 8 bits
	jr	nz, .L.not_zero	; size >= 65536
	; size == 0
	ex	de, hl
	ret