You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
314 lines
9.8 KiB
314 lines
9.8 KiB
@ 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
|
|
|