gbdk-2020 | GameBoy Development Kit |
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gbdk-lib/libc/asm/mos6502/_divslong.s
1 ;-------------------------------------------------------------------------
2 ; _divslong.s - routine 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 _divslong
31
32 ;--------------------------------------------------------
33 ; exported symbols
34 ;--------------------------------------------------------
35 .globl __divslong
36 .globl ___sdivmod32
37
38 ;--------------------------------------------------------
39 ; local aliases
40 ;--------------------------------------------------------
41 .define res0 "__divslong_PARM_1+0"
42 .define res1 "__divslong_PARM_1+1"
43 .define res2 "___SDCC_m6502_ret2"
44 .define res3 "___SDCC_m6502_ret3"
45 .define den "__divslong_PARM_2"
46 .define rem "___SDCC_m6502_ret4"
47 .define s1 "___SDCC_m6502_ret0"
48 .define s2 "___SDCC_m6502_ret1"
49
50 ;--------------------------------------------------------
51 ; code
52 ;--------------------------------------------------------
53 .area _CODE
54 __divslong:
55 jsr ___sdivmod32
56 lda *s1
57 eor *s2
58 bpl pos
59 ; neg res
60 sec
61 lda #0x00
62 sbc *res0
63 tay
64 lda #0x00
65 sbc *res1
66 tax
67 lda #0x00
68 sbc *res2
69 sta *res2
70 lda #0x00
71 sbc *res3
72 sta *res3
73 tya
74 rts
75 pos:
76 lda *res0
77 ldx *res1
78 rts
79
80 ___sdivmod32:
81 lda *__divslong_PARM_1+3
82 sta *s1
83 bpl pos1
84 ldy #0
85 jsr ___neg_div32_param
86 pos1:
87 lda *__divslong_PARM_2+3
88 sta *s2
89 bpl pos2
90 ldy #4
91 jsr ___neg_div32_param
92 pos2:
93 jmp ___udivmod32
94
95 ___neg_div32_param:
96 sec
97 ldx #0x04
98 loop:
99 lda #0x00
100 sbc *__divslong_PARM_1+0,y
101 sta *__divslong_PARM_1+0,y
102 iny
103 dex
104 bne loop
105 rts
106
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