sdcc/device/lib/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