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