356 lines
8.2 KiB
Diff
356 lines
8.2 KiB
Diff
---
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arch/arm/boot/compressed/lib1funcs.S | 348 +++++++++++++++++++++++++++++++++++
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1 file changed, 348 insertions(+)
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--- /dev/null
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+++ linux-2.6.35/arch/arm/boot/compressed/lib1funcs.S
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@@ -0,0 +1,348 @@
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+/*
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+ * linux/arch/arm/lib/lib1funcs.S: Optimized ARM division routines
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+ *
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+ * Author: Nicolas Pitre <nico@fluxnic.net>
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+ * - contributed to gcc-3.4 on Sep 30, 2003
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+ * - adapted for the Linux kernel on Oct 2, 2003
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+ */
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+
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+/* Copyright 1995, 1996, 1998, 1999, 2000, 2003 Free Software Foundation, Inc.
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+
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+This file is free software; you can redistribute it and/or modify it
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+under the terms of the GNU General Public License as published by the
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+Free Software Foundation; either version 2, or (at your option) any
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+later version.
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+
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+In addition to the permissions in the GNU General Public License, the
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+Free Software Foundation gives you unlimited permission to link the
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+compiled version of this file into combinations with other programs,
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+and to distribute those combinations without any restriction coming
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+from the use of this file. (The General Public License restrictions
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+do apply in other respects; for example, they cover modification of
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+the file, and distribution when not linked into a combine
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+executable.)
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+
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+This file is distributed in the hope that it will be useful, but
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+WITHOUT ANY WARRANTY; without even the implied warranty of
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+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+General Public License for more details.
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+
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+You should have received a copy of the GNU General Public License
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+along with this program; see the file COPYING. If not, write to
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+the Free Software Foundation, 59 Temple Place - Suite 330,
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+Boston, MA 02111-1307, USA. */
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+
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+
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+#include <linux/linkage.h>
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+#include <asm/assembler.h>
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+
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+
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+.macro ARM_DIV_BODY dividend, divisor, result, curbit
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+
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+#if __LINUX_ARM_ARCH__ >= 5
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+
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+ clz \curbit, \divisor
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+ clz \result, \dividend
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+ sub \result, \curbit, \result
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+ mov \curbit, #1
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+ mov \divisor, \divisor, lsl \result
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+ mov \curbit, \curbit, lsl \result
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+ mov \result, #0
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+
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+#else
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+
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+ @ Initially shift the divisor left 3 bits if possible,
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+ @ set curbit accordingly. This allows for curbit to be located
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+ @ at the left end of each 4 bit nibbles in the division loop
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+ @ to save one loop in most cases.
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+ tst \divisor, #0xe0000000
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+ moveq \divisor, \divisor, lsl #3
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+ moveq \curbit, #8
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+ movne \curbit, #1
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+
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+ @ Unless the divisor is very big, shift it up in multiples of
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+ @ four bits, since this is the amount of unwinding in the main
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+ @ division loop. Continue shifting until the divisor is
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+ @ larger than the dividend.
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+1: cmp \divisor, #0x10000000
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+ cmplo \divisor, \dividend
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+ movlo \divisor, \divisor, lsl #4
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+ movlo \curbit, \curbit, lsl #4
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+ blo 1b
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+
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+ @ For very big divisors, we must shift it a bit at a time, or
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+ @ we will be in danger of overflowing.
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+1: cmp \divisor, #0x80000000
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+ cmplo \divisor, \dividend
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+ movlo \divisor, \divisor, lsl #1
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+ movlo \curbit, \curbit, lsl #1
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+ blo 1b
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+
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+ mov \result, #0
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+
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+#endif
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+
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+ @ Division loop
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+1: cmp \dividend, \divisor
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+ subhs \dividend, \dividend, \divisor
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+ orrhs \result, \result, \curbit
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+ cmp \dividend, \divisor, lsr #1
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+ subhs \dividend, \dividend, \divisor, lsr #1
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+ orrhs \result, \result, \curbit, lsr #1
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+ cmp \dividend, \divisor, lsr #2
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+ subhs \dividend, \dividend, \divisor, lsr #2
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+ orrhs \result, \result, \curbit, lsr #2
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+ cmp \dividend, \divisor, lsr #3
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+ subhs \dividend, \dividend, \divisor, lsr #3
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+ orrhs \result, \result, \curbit, lsr #3
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+ cmp \dividend, #0 @ Early termination?
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+ movnes \curbit, \curbit, lsr #4 @ No, any more bits to do?
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+ movne \divisor, \divisor, lsr #4
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+ bne 1b
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+
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+.endm
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+
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+
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+.macro ARM_DIV2_ORDER divisor, order
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+
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+#if __LINUX_ARM_ARCH__ >= 5
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+
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+ clz \order, \divisor
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+ rsb \order, \order, #31
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+
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+#else
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+
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+ cmp \divisor, #(1 << 16)
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+ movhs \divisor, \divisor, lsr #16
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+ movhs \order, #16
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+ movlo \order, #0
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+
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+ cmp \divisor, #(1 << 8)
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+ movhs \divisor, \divisor, lsr #8
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+ addhs \order, \order, #8
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+
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+ cmp \divisor, #(1 << 4)
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+ movhs \divisor, \divisor, lsr #4
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+ addhs \order, \order, #4
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+
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+ cmp \divisor, #(1 << 2)
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+ addhi \order, \order, #3
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+ addls \order, \order, \divisor, lsr #1
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+
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+#endif
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+
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+.endm
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+
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+
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+.macro ARM_MOD_BODY dividend, divisor, order, spare
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+
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+#if __LINUX_ARM_ARCH__ >= 5
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+
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+ clz \order, \divisor
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+ clz \spare, \dividend
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+ sub \order, \order, \spare
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+ mov \divisor, \divisor, lsl \order
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+
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+#else
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+
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+ mov \order, #0
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+
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+ @ Unless the divisor is very big, shift it up in multiples of
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+ @ four bits, since this is the amount of unwinding in the main
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+ @ division loop. Continue shifting until the divisor is
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+ @ larger than the dividend.
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+1: cmp \divisor, #0x10000000
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+ cmplo \divisor, \dividend
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+ movlo \divisor, \divisor, lsl #4
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+ addlo \order, \order, #4
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+ blo 1b
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+
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+ @ For very big divisors, we must shift it a bit at a time, or
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+ @ we will be in danger of overflowing.
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+1: cmp \divisor, #0x80000000
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+ cmplo \divisor, \dividend
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+ movlo \divisor, \divisor, lsl #1
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+ addlo \order, \order, #1
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+ blo 1b
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+
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+#endif
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+
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+ @ Perform all needed substractions to keep only the reminder.
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+ @ Do comparisons in batch of 4 first.
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+ subs \order, \order, #3 @ yes, 3 is intended here
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+ blt 2f
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+
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+1: cmp \dividend, \divisor
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+ subhs \dividend, \dividend, \divisor
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+ cmp \dividend, \divisor, lsr #1
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+ subhs \dividend, \dividend, \divisor, lsr #1
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+ cmp \dividend, \divisor, lsr #2
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+ subhs \dividend, \dividend, \divisor, lsr #2
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+ cmp \dividend, \divisor, lsr #3
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+ subhs \dividend, \dividend, \divisor, lsr #3
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+ cmp \dividend, #1
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+ mov \divisor, \divisor, lsr #4
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+ subges \order, \order, #4
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+ bge 1b
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+
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+ tst \order, #3
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+ teqne \dividend, #0
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+ beq 5f
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+
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+ @ Either 1, 2 or 3 comparison/substractions are left.
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+2: cmn \order, #2
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+ blt 4f
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+ beq 3f
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+ cmp \dividend, \divisor
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+ subhs \dividend, \dividend, \divisor
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+ mov \divisor, \divisor, lsr #1
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+3: cmp \dividend, \divisor
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+ subhs \dividend, \dividend, \divisor
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+ mov \divisor, \divisor, lsr #1
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+4: cmp \dividend, \divisor
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+ subhs \dividend, \dividend, \divisor
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+5:
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+.endm
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+
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+
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+ENTRY(__udivsi3)
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+ENTRY(__aeabi_uidiv)
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+
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+ subs r2, r1, #1
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+ moveq pc, lr
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+ bcc Ldiv0
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+ cmp r0, r1
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+ bls 11f
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+ tst r1, r2
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+ beq 12f
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+
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+ ARM_DIV_BODY r0, r1, r2, r3
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+
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+ mov r0, r2
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+ mov pc, lr
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+
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+11: moveq r0, #1
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+ movne r0, #0
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+ mov pc, lr
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+
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+12: ARM_DIV2_ORDER r1, r2
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+
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+ mov r0, r0, lsr r2
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+ mov pc, lr
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+
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+ENDPROC(__udivsi3)
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+ENDPROC(__aeabi_uidiv)
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+
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+ENTRY(__umodsi3)
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+
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+ subs r2, r1, #1 @ compare divisor with 1
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+ bcc Ldiv0
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+ cmpne r0, r1 @ compare dividend with divisor
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+ moveq r0, #0
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+ tsthi r1, r2 @ see if divisor is power of 2
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+ andeq r0, r0, r2
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+ movls pc, lr
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+
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+ ARM_MOD_BODY r0, r1, r2, r3
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+
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+ mov pc, lr
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+
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+ENDPROC(__umodsi3)
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+
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+ENTRY(__divsi3)
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+ENTRY(__aeabi_idiv)
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+
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+ cmp r1, #0
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+ eor ip, r0, r1 @ save the sign of the result.
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+ beq Ldiv0
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+ rsbmi r1, r1, #0 @ loops below use unsigned.
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+ subs r2, r1, #1 @ division by 1 or -1 ?
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+ beq 10f
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+ movs r3, r0
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+ rsbmi r3, r0, #0 @ positive dividend value
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+ cmp r3, r1
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+ bls 11f
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+ tst r1, r2 @ divisor is power of 2 ?
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+ beq 12f
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+
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+ ARM_DIV_BODY r3, r1, r0, r2
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+
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+ cmp ip, #0
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+ rsbmi r0, r0, #0
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+ mov pc, lr
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+
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+10: teq ip, r0 @ same sign ?
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+ rsbmi r0, r0, #0
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+ mov pc, lr
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+
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+11: movlo r0, #0
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+ moveq r0, ip, asr #31
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+ orreq r0, r0, #1
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+ mov pc, lr
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+
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+12: ARM_DIV2_ORDER r1, r2
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+
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+ cmp ip, #0
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+ mov r0, r3, lsr r2
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+ rsbmi r0, r0, #0
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+ mov pc, lr
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+
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+ENDPROC(__divsi3)
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+ENDPROC(__aeabi_idiv)
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+
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+ENTRY(__modsi3)
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+
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+ cmp r1, #0
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+ beq Ldiv0
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+ rsbmi r1, r1, #0 @ loops below use unsigned.
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+ movs ip, r0 @ preserve sign of dividend
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+ rsbmi r0, r0, #0 @ if negative make positive
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+ subs r2, r1, #1 @ compare divisor with 1
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+ cmpne r0, r1 @ compare dividend with divisor
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+ moveq r0, #0
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+ tsthi r1, r2 @ see if divisor is power of 2
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+ andeq r0, r0, r2
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+ bls 10f
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+
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+ ARM_MOD_BODY r0, r1, r2, r3
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+
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+10: cmp ip, #0
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+ rsbmi r0, r0, #0
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+ mov pc, lr
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+
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+ENDPROC(__modsi3)
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+
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+#ifdef CONFIG_AEABI
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+
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+ENTRY(__aeabi_uidivmod)
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+
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+ stmfd sp!, {r0, r1, ip, lr}
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+ bl __aeabi_uidiv
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+ ldmfd sp!, {r1, r2, ip, lr}
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+ mul r3, r0, r2
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+ sub r1, r1, r3
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+ mov pc, lr
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+
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+ENDPROC(__aeabi_uidivmod)
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+
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+ENTRY(__aeabi_idivmod)
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+
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+ stmfd sp!, {r0, r1, ip, lr}
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+ bl __aeabi_idiv
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+ ldmfd sp!, {r1, r2, ip, lr}
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+ mul r3, r0, r2
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+ sub r1, r1, r3
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+ mov pc, lr
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+
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+ENDPROC(__aeabi_idivmod)
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+
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+#endif
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+
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+Ldiv0:
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+
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+ str lr, [sp, #-8]!
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+ bl __div0
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+ mov r0, #0 @ About as wrong as it could be.
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+ ldr pc, [sp], #8
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+
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+
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