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