gbdk-2020 | GameBoy Development Kit |
| download: https://git.y1.nz/archives/gbdk.tar.gz | |
| README | Files | Log | Refs | LICENSE |
gbdk-lib/libc/asm/mos6502/__memcpy.s
1 ;-------------------------------------------------------------------------
2 ; memcpy.s - standarc C library
3 ;
4 ; Copyright (C) 2003, Ullrich von Bassewitz
5 ; Copyright (C) 2009, Christian Krueger
6 ; Copyright (C) 2022, Gabriele Gorla
7 ;
8 ; This library is free software; you can redistribute it and/or modify it
9 ; under the terms of the GNU General Public License as published by the
10 ; Free Software Foundation; either version 2, or (at your option) any
11 ; later version.
12 ;
13 ; This library is distributed in the hope that it will be useful,
14 ; but WITHOUT ANY WARRANTY; without even the implied warranty of
15 ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 ; GNU General Public License for more details.
17 ;
18 ; You should have received a copy of the GNU General Public License
19 ; along with this library; see the file COPYING. If not, write to the
20 ; Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
21 ; MA 02110-1301, USA.
22 ;
23 ; As a special exception, if you link this library with other files,
24 ; some of which are compiled with SDCC, to produce an executable,
25 ; this library does not by itself cause the resulting executable to
26 ; be covered by the GNU General Public License. This exception does
27 ; not however invalidate any other reasons why the executable file
28 ; might be covered by the GNU General Public License.
29 ;-------------------------------------------------------------------------
30
31 .module ___memcpy
32
33 ;--------------------------------------------------------
34 ; exported symbols
35 ;--------------------------------------------------------
36 .globl ___memcpy_PARM_2
37 .globl ___memcpy_PARM_3
38 .globl ___memcpy
39
40 ;--------------------------------------------------------
41 ; overlayable function paramters in zero page
42 ;--------------------------------------------------------
43 .area OSEG (PAG, OVR)
44 ___memcpy_PARM_2:
45 .ds 2
46 ___memcpy_PARM_3:
47 .ds 2
48
49 ;--------------------------------------------------------
50 ; local aliases
51 ;--------------------------------------------------------
52 .define save "___SDCC_m6502_ret0"
53 .define dst "___SDCC_m6502_ret2"
54 .define src "___memcpy_PARM_2"
55 .define count "___memcpy_PARM_3"
56
57 ;--------------------------------------------------------
58 ; code
59 ;--------------------------------------------------------
60 .area _CODE
61
62 ___memcpy:
63 sta *save+0
64 stx *save+1
65 sta *dst+0
66 stx *dst+1
67
68 ldy #0
69 ldx *count+1
70 beq L2
71 L1:
72 lda [*src],y
73 sta [*dst],y
74 iny
75 lda [*src],y
76 sta [*dst],y
77 iny
78 bne L1
79 inc *src+1
80 inc *dst+1
81 dex
82 bne L1
83 L2:
84 ldx *count+0
85 beq done
86 L3:
87 lda [*src],y
88 sta [*dst],y
89 iny
90 dex
91 bne L3
92 done:
93 lda *save+0
94 ldx *save+1
95 rts
This webpage is intended to be an accessible preview of this repository. To get a fuller picture, clone it and use the git CLI.