patch-2.4.13 linux/arch/arm/lib/lib1funcs.S

• Lines: 321
• Date: Thu Oct 11 09:04:57 2001
• Orig file: v2.4.12/linux/arch/arm/lib/lib1funcs.S
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.12/linux/arch/arm/lib/lib1funcs.S linux/arch/arm/lib/lib1funcs.S
@@ -0,0 +1,320 @@
+@ 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>
+
+#ifdef CONFIG_CPU_26
+#define RET	movs
+#define RETc(x)	mov##x##s
+#define RETCOND ^
+#else
+#define RET	mov
+#define RETc(x)	mov##x
+#define RETCOND
+#endif
+
+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