| /* 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__ */ |
| |
