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Diffstat (limited to 'arch/arm26/lib/lib1funcs.S')

-rw-r--r-- | arch/arm26/lib/lib1funcs.S | 314 |

1 files changed, 314 insertions, 0 deletions

diff --git a/arch/arm26/lib/lib1funcs.S b/arch/arm26/lib/lib1funcs.S new file mode 100644 index 00000000000..b8f9518db87 --- /dev/null +++ b/arch/arm26/lib/lib1funcs.S @@ -0,0 +1,314 @@ +@ libgcc1 routines for ARM cpu. +@ Division routines, written by Richard Earnshaw, (rearnsha@armltd.co.uk) + +/* Copyright (C) 1995, 1996, 1998 Free Software Foundation, Inc. + +This file 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. + +You should have received a copy of the GNU General Public License +along with this program; see the file COPYING. If not, write to +the Free Software Foundation, 59 Temple Place - Suite 330, +Boston, MA 02111-1307, USA. */ + +/* As a special exception, if you link this library with other files, + some of which are compiled with GCC, to produce an executable, + this library does not by itself 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. + */ +/* This code is derived from gcc 2.95.3 */ +/* I Molton 29/07/01 */ + +#include <linux/linkage.h> +#include <asm/assembler.h> +#include <asm/hardware.h> +#include <linux/config.h> + +#define RET movs +#define RETc(x) mov##x##s +#define RETCOND ^ + +dividend .req r0 +divisor .req r1 +result .req r2 +overdone .req r2 +curbit .req r3 +ip .req r12 +sp .req r13 +lr .req r14 +pc .req r15 + +ENTRY(__udivsi3) + cmp divisor, #0 + beq Ldiv0 + mov curbit, #1 + mov result, #0 + cmp dividend, divisor + bcc Lgot_result_udivsi3 +1: + @ Unless the divisor is very big, shift it up in multiples of + @ four bits, since this is the amount of unwinding in the main + @ division loop. Continue shifting until the divisor is + @ larger than the dividend. + cmp divisor, #0x10000000 + cmpcc divisor, dividend + movcc divisor, divisor, lsl #4 + movcc curbit, curbit, lsl #4 + bcc 1b + +2: + @ For very big divisors, we must shift it a bit at a time, or + @ we will be in danger of overflowing. + cmp divisor, #0x80000000 + cmpcc divisor, dividend + movcc divisor, divisor, lsl #1 + movcc curbit, curbit, lsl #1 + bcc 2b + +3: + @ Test for possible subtractions, and note which bits + @ are done in the result. On the final pass, this may subtract + @ too much from the dividend, but the result will be ok, since the + @ "bit" will have been shifted out at the bottom. + cmp dividend, divisor + subcs dividend, dividend, divisor + orrcs result, result, curbit + cmp dividend, divisor, lsr #1 + subcs dividend, dividend, divisor, lsr #1 + orrcs result, result, curbit, lsr #1 + cmp dividend, divisor, lsr #2 + subcs dividend, dividend, divisor, lsr #2 + orrcs result, result, curbit, lsr #2 + cmp dividend, divisor, lsr #3 + subcs dividend, dividend, divisor, lsr #3 + orrcs result, result, curbit, lsr #3 + cmp dividend, #0 @ Early termination? + movnes curbit, curbit, lsr #4 @ No, any more bits to do? + movne divisor, divisor, lsr #4 + bne 3b +Lgot_result_udivsi3: + mov r0, result + RET pc, lr + +Ldiv0: + str lr, [sp, #-4]! + bl __div0 + mov r0, #0 @ about as wrong as it could be + ldmia sp!, {pc}RETCOND + +/* __umodsi3 ----------------------- */ + +ENTRY(__umodsi3) + cmp divisor, #0 + beq Ldiv0 + mov curbit, #1 + cmp dividend, divisor + RETc(cc) pc, lr +1: + @ Unless the divisor is very big, shift it up in multiples of + @ four bits, since this is the amount of unwinding in the main + @ division loop. Continue shifting until the divisor is + @ larger than the dividend. + cmp divisor, #0x10000000 + cmpcc divisor, dividend + movcc divisor, divisor, lsl #4 + movcc curbit, curbit, lsl #4 + bcc 1b + +2: + @ For very big divisors, we must shift it a bit at a time, or + @ we will be in danger of overflowing. + cmp divisor, #0x80000000 + cmpcc divisor, dividend + movcc divisor, divisor, lsl #1 + movcc curbit, curbit, lsl #1 + bcc 2b + +3: + @ Test for possible subtractions. On the final pass, this may + @ subtract too much from the dividend, so keep track of which + @ subtractions are done, we can fix them up afterwards... + mov overdone, #0 + cmp dividend, divisor + subcs dividend, dividend, divisor + cmp dividend, divisor, lsr #1 + subcs dividend, dividend, divisor, lsr #1 + orrcs overdone, overdone, curbit, ror #1 + cmp dividend, divisor, lsr #2 + subcs dividend, dividend, divisor, lsr #2 + orrcs overdone, overdone, curbit, ror #2 + cmp dividend, divisor, lsr #3 + subcs dividend, dividend, divisor, lsr #3 + orrcs overdone, overdone, curbit, ror #3 + mov ip, curbit + cmp dividend, #0 @ Early termination? + movnes curbit, curbit, lsr #4 @ No, any more bits to do? + movne divisor, divisor, lsr #4 + bne 3b + + @ Any subtractions that we should not have done will be recorded in + @ the top three bits of "overdone". Exactly which were not needed + @ are governed by the position of the bit, stored in ip. + @ If we terminated early, because dividend became zero, + @ then none of the below will match, since the bit in ip will not be + @ in the bottom nibble. + ands overdone, overdone, #0xe0000000 + RETc(eq) pc, lr @ No fixups needed + tst overdone, ip, ror #3 + addne dividend, dividend, divisor, lsr #3 + tst overdone, ip, ror #2 + addne dividend, dividend, divisor, lsr #2 + tst overdone, ip, ror #1 + addne dividend, dividend, divisor, lsr #1 + RET pc, lr + +ENTRY(__divsi3) + eor ip, dividend, divisor @ Save the sign of the result. + mov curbit, #1 + mov result, #0 + cmp divisor, #0 + rsbmi divisor, divisor, #0 @ Loops below use unsigned. + beq Ldiv0 + cmp dividend, #0 + rsbmi dividend, dividend, #0 + cmp dividend, divisor + bcc Lgot_result_divsi3 + +1: + @ Unless the divisor is very big, shift it up in multiples of + @ four bits, since this is the amount of unwinding in the main + @ division loop. Continue shifting until the divisor is + @ larger than the dividend. + cmp divisor, #0x10000000 + cmpcc divisor, dividend + movcc divisor, divisor, lsl #4 + movcc curbit, curbit, lsl #4 + bcc 1b + +2: + @ For very big divisors, we must shift it a bit at a time, or + @ we will be in danger of overflowing. + cmp divisor, #0x80000000 + cmpcc divisor, dividend + movcc divisor, divisor, lsl #1 + movcc curbit, curbit, lsl #1 + bcc 2b + +3: + @ Test for possible subtractions, and note which bits + @ are done in the result. On the final pass, this may subtract + @ too much from the dividend, but the result will be ok, since the + @ "bit" will have been shifted out at the bottom. + cmp dividend, divisor + subcs dividend, dividend, divisor + orrcs result, result, curbit + cmp dividend, divisor, lsr #1 + subcs dividend, dividend, divisor, lsr #1 + orrcs result, result, curbit, lsr #1 + cmp dividend, divisor, lsr #2 + subcs dividend, dividend, divisor, lsr #2 + orrcs result, result, curbit, lsr #2 + cmp dividend, divisor, lsr #3 + subcs dividend, dividend, divisor, lsr #3 + orrcs result, result, curbit, lsr #3 + cmp dividend, #0 @ Early termination? + movnes curbit, curbit, lsr #4 @ No, any more bits to do? + movne divisor, divisor, lsr #4 + bne 3b +Lgot_result_divsi3: + mov r0, result + cmp ip, #0 + rsbmi r0, r0, #0 + RET pc, lr + +ENTRY(__modsi3) + mov curbit, #1 + cmp divisor, #0 + rsbmi divisor, divisor, #0 @ Loops below use unsigned. + beq Ldiv0 + @ Need to save the sign of the dividend, unfortunately, we need + @ ip later on; this is faster than pushing lr and using that. + str dividend, [sp, #-4]! + cmp dividend, #0 + rsbmi dividend, dividend, #0 + cmp dividend, divisor + bcc Lgot_result_modsi3 + +1: + @ Unless the divisor is very big, shift it up in multiples of + @ four bits, since this is the amount of unwinding in the main + @ division loop. Continue shifting until the divisor is + @ larger than the dividend. + cmp divisor, #0x10000000 + cmpcc divisor, dividend + movcc divisor, divisor, lsl #4 + movcc curbit, curbit, lsl #4 + bcc 1b + +2: + @ For very big divisors, we must shift it a bit at a time, or + @ we will be in danger of overflowing. + cmp divisor, #0x80000000 + cmpcc divisor, dividend + movcc divisor, divisor, lsl #1 + movcc curbit, curbit, lsl #1 + bcc 2b + +3: + @ Test for possible subtractions. On the final pass, this may + @ subtract too much from the dividend, so keep track of which + @ subtractions are done, we can fix them up afterwards... + mov overdone, #0 + cmp dividend, divisor + subcs dividend, dividend, divisor + cmp dividend, divisor, lsr #1 + subcs dividend, dividend, divisor, lsr #1 + orrcs overdone, overdone, curbit, ror #1 + cmp dividend, divisor, lsr #2 + subcs dividend, dividend, divisor, lsr #2 + orrcs overdone, overdone, curbit, ror #2 + cmp dividend, divisor, lsr #3 + subcs dividend, dividend, divisor, lsr #3 + orrcs overdone, overdone, curbit, ror #3 + mov ip, curbit + cmp dividend, #0 @ Early termination? + movnes curbit, curbit, lsr #4 @ No, any more bits to do? + movne divisor, divisor, lsr #4 + bne 3b + + @ Any subtractions that we should not have done will be recorded in + @ the top three bits of "overdone". Exactly which were not needed + @ are governed by the position of the bit, stored in ip. + @ If we terminated early, because dividend became zero, + @ then none of the below will match, since the bit in ip will not be + @ in the bottom nibble. + ands overdone, overdone, #0xe0000000 + beq Lgot_result_modsi3 + tst overdone, ip, ror #3 + addne dividend, dividend, divisor, lsr #3 + tst overdone, ip, ror #2 + addne dividend, dividend, divisor, lsr #2 + tst overdone, ip, ror #1 + addne dividend, dividend, divisor, lsr #1 +Lgot_result_modsi3: + ldr ip, [sp], #4 + cmp ip, #0 + rsbmi dividend, dividend, #0 + RET pc, lr |