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Diffstat (limited to 'arch/m68k/lib/udivsi3.S')
| -rw-r--r-- | arch/m68k/lib/udivsi3.S | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/arch/m68k/lib/udivsi3.S b/arch/m68k/lib/udivsi3.S new file mode 100644 index 000000000..35a544657 --- /dev/null +++ b/arch/m68k/lib/udivsi3.S @@ -0,0 +1,157 @@ +/* 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__ */ + |