1/* libgcc1 routines for 68000 w/o floating-point hardware. 2 Copyright (C) 1994, 1996, 1997, 1998 Free Software Foundation, Inc. 3 4This file is part of GNU CC. 5 6GNU CC is free software; you can redistribute it and/or modify it 7under the terms of the GNU General Public License as published by the 8Free Software Foundation; either version 2, or (at your option) any 9later version. 10 11In addition to the permissions in the GNU General Public License, the 12Free Software Foundation gives you unlimited permission to link the 13compiled version of this file with other programs, and to distribute 14those programs without any restriction coming from the use of this 15file. (The General Public License restrictions do apply in other 16respects; for example, they cover modification of the file, and 17distribution when not linked into another program.) 18 19This file is distributed in the hope that it will be useful, but 20WITHOUT ANY WARRANTY; without even the implied warranty of 21MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 22General Public License for more details. 23 24You should have received a copy of the GNU General Public License 25along with this program; see the file COPYING. If not, write to 26the Free Software Foundation, 59 Temple Place - Suite 330, 27Boston, MA 02111-1307, USA. */ 28 29/* As a special exception, if you link this library with files 30 compiled with GCC to produce an executable, this does not cause 31 the resulting executable to be covered by the GNU General Public License. 32 This exception does not however invalidate any other reasons why 33 the executable file might be covered by the GNU General Public License. */ 34 35/* Use this one for any 680x0; assumes no floating point hardware. 36 The trailing " '" appearing on some lines is for ANSI preprocessors. Yuk. 37 Some of this code comes from MINIX, via the folks at ericsson. 38 D. V. Henkel-Wallace (gumby@cygnus.com) Fete Bastille, 1992 39*/ 40 41/* These are predefined by new versions of GNU cpp. */ 42 43#ifndef __USER_LABEL_PREFIX__ 44#define __USER_LABEL_PREFIX__ _ 45#endif 46 47#ifndef __REGISTER_PREFIX__ 48#define __REGISTER_PREFIX__ 49#endif 50 51#ifndef __IMMEDIATE_PREFIX__ 52#define __IMMEDIATE_PREFIX__ # 53#endif 54 55/* ANSI concatenation macros. */ 56 57#define CONCAT1(a, b) CONCAT2(a, b) 58#define CONCAT2(a, b) a ## b 59 60/* Use the right prefix for global labels. */ 61 62#define SYM(x) CONCAT1 (__USER_LABEL_PREFIX__, x) 63 64/* Use the right prefix for registers. */ 65 66#define REG(x) CONCAT1 (__REGISTER_PREFIX__, x) 67 68/* Use the right prefix for immediate values. */ 69 70#define IMM(x) CONCAT1 (__IMMEDIATE_PREFIX__, x) 71 72#define d0 REG (d0) 73#define d1 REG (d1) 74#define d2 REG (d2) 75#define d3 REG (d3) 76#define d4 REG (d4) 77#define d5 REG (d5) 78#define d6 REG (d6) 79#define d7 REG (d7) 80#define a0 REG (a0) 81#define a1 REG (a1) 82#define a2 REG (a2) 83#define a3 REG (a3) 84#define a4 REG (a4) 85#define a5 REG (a5) 86#define a6 REG (a6) 87#define fp REG (fp) 88#define sp REG (sp) 89 90 .text 91 .proc 92 .globl SYM (__udivsi3) 93SYM (__udivsi3): 94#if !(defined(__mcf5200__) || defined(__mcoldfire__)) 95 movel d2, sp@- 96 movel sp@(12), d1 /* d1 = divisor */ 97 movel sp@(8), d0 /* d0 = dividend */ 98 99 cmpl IMM (0x10000), d1 /* divisor >= 2 ^ 16 ? */ 100 jcc L3 /* then try next algorithm */ 101 movel d0, d2 102 clrw d2 103 swap d2 104 divu d1, d2 /* high quotient in lower word */ 105 movew d2, d0 /* save high quotient */ 106 swap d0 107 movew sp@(10), d2 /* get low dividend + high rest */ 108 divu d1, d2 /* low quotient */ 109 movew d2, d0 110 jra L6 111 112L3: movel d1, d2 /* use d2 as divisor backup */ 113L4: lsrl IMM (1), d1 /* shift divisor */ 114 lsrl IMM (1), d0 /* shift dividend */ 115 cmpl IMM (0x10000), d1 /* still divisor >= 2 ^ 16 ? */ 116 jcc L4 117 divu d1, d0 /* now we have 16 bit divisor */ 118 andl IMM (0xffff), d0 /* mask out divisor, ignore remainder */ 119 120/* Multiply the 16 bit tentative quotient with the 32 bit divisor. Because of 121 the operand ranges, this might give a 33 bit product. If this product is 122 greater than the dividend, the tentative quotient was too large. */ 123 movel d2, d1 124 mulu d0, d1 /* low part, 32 bits */ 125 swap d2 126 mulu d0, d2 /* high part, at most 17 bits */ 127 swap d2 /* align high part with low part */ 128 tstw d2 /* high part 17 bits? */ 129 jne L5 /* if 17 bits, quotient was too large */ 130 addl d2, d1 /* add parts */ 131 jcs L5 /* if sum is 33 bits, quotient was too large */ 132 cmpl sp@(8), d1 /* compare the sum with the dividend */ 133 jls L6 /* if sum > dividend, quotient was too large */ 134L5: subql IMM (1), d0 /* adjust quotient */ 135 136L6: movel sp@+, d2 137 rts 138 139#else /* __mcf5200__ || __mcoldfire__ */ 140 141/* Coldfire implementation of non-restoring division algorithm from 142 Hennessy & Patterson, Appendix A. */ 143 link a6,IMM (-12) 144 moveml d2-d4,sp@ 145 movel a6@(8),d0 146 movel a6@(12),d1 147 clrl d2 | clear p 148 moveq IMM (31),d4 149L1: addl d0,d0 | shift reg pair (p,a) one bit left 150 addxl d2,d2 151 movl d2,d3 | subtract b from p, store in tmp. 152 subl d1,d3 153 jcs L2 | if no carry, 154 bset IMM (0),d0 | set the low order bit of a to 1, 155 movl d3,d2 | and store tmp in p. 156L2: subql IMM (1),d4 157 jcc L1 158 moveml sp@,d2-d4 | restore data registers 159 unlk a6 | and return 160 rts 161#endif /* __mcf5200__ || __mcoldfire__ */ 162 163