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