gbdk-2020 | GameBoy Development Kit |
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gbdk-lib/libc/asm/mos6502/_modslong.s
1 ;-------------------------------------------------------------------------
2 ; _modslong.s - routine for remainder for 32 bit signed long division
3 ;
4 ; Copyright (C) 1998, Ullrich von Bassewitz
5 ; Copyright (C) 2022, Gabriele Gorla
6 ;
7 ; This library is free software; you can redistribute it and/or modify it
8 ; under the terms of the GNU General Public License as published by the
9 ; Free Software Foundation; either version 2, or (at your option) any
10 ; later version.
11 ;
12 ; This library is distributed in the hope that it will be useful,
13 ; but WITHOUT ANY WARRANTY; without even the implied warranty of
14 ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 ; GNU General Public License for more details.
16 ;
17 ; You should have received a copy of the GNU General Public License
18 ; along with this library; see the file COPYING. If not, write to the
19 ; Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
20 ; MA 02110-1301, USA.
21 ;
22 ; As a special exception, if you link this library with other files,
23 ; some of which are compiled with SDCC, to produce an executable,
24 ; this library does not by itself cause the resulting executable to
25 ; be covered by the GNU General Public License. This exception does
26 ; not however invalidate any other reasons why the executable file
27 ; might be covered by the GNU General Public License.
28 ;-------------------------------------------------------------------------
29
30 .module _modslong
31
32 ;--------------------------------------------------------
33 ; exported symbols
34 ;--------------------------------------------------------
35 .globl __modslong
36
37 ;--------------------------------------------------------
38 ; local aliases
39 ;--------------------------------------------------------
40 .define res0 "__divslong_PARM_1+0"
41 .define res1 "__divslong_PARM_1+1"
42 .define res2 "___SDCC_m6502_ret2"
43 .define res3 "___SDCC_m6502_ret3"
44 .define den "__divslong_PARM_2"
45 .define rem "___SDCC_m6502_ret4"
46 .define s1 "___SDCC_m6502_ret0"
47 .define s2 "___SDCC_m6502_ret1"
48
49 ;--------------------------------------------------------
50 ; code
51 ;--------------------------------------------------------
52 .area _CODE
53 __modslong:
54 jsr ___sdivmod32
55 lda *s1
56 bpl pos
57 ; neg res
58 sec
59 lda #0x00
60 sbc *rem+0
61 tay
62 lda #0x00
63 sbc *rem+1
64 tax
65 lda #0x00
66 sbc *rem+2
67 sta *res2
68 lda #0x00
69 sbc *rem+3
70 sta *res3
71 tya
72 rts
73 pos:
74 lda *rem+3
75 sta *res3
76 lda *rem+2
77 sta *res2
78 ldx *rem+1
79 lda *rem+0
80 rts
81
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