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Diffstat (limited to 'apps/codecs/lib/udiv32_armv4.S')
| -rw-r--r-- | apps/codecs/lib/udiv32_armv4.S | 134 |
1 files changed, 0 insertions, 134 deletions
diff --git a/apps/codecs/lib/udiv32_armv4.S b/apps/codecs/lib/udiv32_armv4.S deleted file mode 100644 index c4aea14093..0000000000 --- a/apps/codecs/lib/udiv32_armv4.S +++ /dev/null @@ -1,134 +0,0 @@ -/*************************************************************************** - * __________ __ ___. - * Open \______ \ ____ ____ | | _\_ |__ _______ ___ - * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / - * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < - * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ - * \/ \/ \/ \/ \/ - * $Id$ - * - * Copyright (C) 2008 by Jens Arnold - * Copyright (C) 2009 by Andrew Mahone - * - * Optimised unsigned integer division for ARMv4 - * - * Based on: libgcc routines for ARM cpu. - * Division routines, written by Richard Earnshaw, (rearnsha@armltd.co.uk) - * Copyright 1995, 1996, 1998, 1999, 2000, 2003, 2004, 2005 - * Free Software Foundation, Inc. - * - * This program 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 - * of the License, or (at your option) any later version. - * - * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY - * KIND, either express or implied. - * - ****************************************************************************/ - -#include "config.h" -/* Codecs should not normally do this, but we need to check a macro, and - * codecs.h would confuse the assembler. */ - -/* Adapted from an algorithm given in ARM System Developer's Guide (7.3.1.2) - for dividing a 30-bit value by a 15-bit value, with two operations per - iteration by storing quotient and remainder together and adding the previous - quotient bit during trial subtraction. Modified to work with any dividend - and divisor both less than 1 << 30, and skipping trials by calculating bits - in output. */ -.macro ARM_DIV_31_BODY dividend, divisor, result, bits, curbit, quotient, remainder - - mov \bits, #1 - /* Shift the divisor left until it aligns with the numerator. If it already - has the high bit set, this is fine, everything inside .rept will be - skipped, and the add before and adcs after will set the one-bit result - to zero. */ - cmn \divisor, \dividend, lsr #16 - movcs \divisor, \divisor, lsl #16 - addcs \bits, \bits, #16 - cmn \divisor, \dividend, lsr #8 - movcs \divisor, \divisor, lsl #8 - addcs \bits, \bits, #8 - cmn \divisor, \dividend, lsr #4 - movcs \divisor, \divisor, lsl #4 - addcs \bits, \bits, #4 - cmn \divisor, \dividend, lsr #2 - movcs \divisor, \divisor, lsl #2 - addcs \bits, \bits, #2 - cmn \divisor, \dividend, lsr #1 - movcs \divisor, \divisor, lsl #1 - addcs \bits, \bits, #1 - adds \result, \dividend, \divisor - subcc \result, \result, \divisor - rsb \curbit, \bits, #31 - add pc, pc, \curbit, lsl #3 - nop - .rept 30 - adcs \result, \divisor, \result, lsl #1 - /* Fix the remainder portion of the result. This must be done because the - handler for 32-bit numerators needs the remainder. */ - subcc \result, \result, \divisor - .endr - /* Shift remainder/quotient left one, add final quotient bit */ - adc \result, \result, \result - mov \remainder, \result, lsr \bits - eor \quotient, \result, \remainder, lsl \bits -.endm - -#ifdef USE_IRAM - .section .icode,"ax",%progbits -#else - .text -#endif - .align - .global udiv32_arm - .type udiv32_arm,%function - -udiv32_arm: - /* Invert divisor. ARM_DIV_31_BODY uses adc to both subtract the divisor - and add the next bit of the result. The correction code at .L_udiv32 - does not need the divisor inverted, but can be modified to work with it, - and this allows the zero divisor test to be done early and without an - explicit comparison. */ - rsbs r1, r1, #0 - beq .L_div0 - tst r0, r0 - /* High bit must be unset, otherwise shift numerator right, calculate, - and correct results. As this case is very uncommon we want to avoid - any other delays on the main path in handling it, so the long divide - calls the short divide as a function. */ - bmi .L_udiv32 -.L_udiv31: - ARM_DIV_31_BODY r0, r1, r2, r3, ip, r0, r1 - bx lr - -.L_udiv32: - /* store original numerator and divisor, we'll need them to correct the - result, */ - stmdb sp, { r0, r1, lr } - /* Call __div0 here if divisor is zero, otherwise it would report the wrong - address. */ - mov r0, r0, lsr #1 - bl .L_udiv31 - ldmdb sp, { r2, r3, lr } - /* Move the low bit of the original numerator to the carry bit */ - movs r2, r2, lsr #1 - /* Shift the remainder left one and add in the carry bit */ - adc r1, r1, r1 - /* Subtract the original divisor from the remainder, setting carry if the - result is non-negative */ - adds r1, r1, r3 - /* Shift quotient left one and add carry bit */ - adc r0, r0, r0 - bx lr -.L_div0: - /* __div0 expects the calling address on the top of the stack */ - stmdb sp!, { lr } -#if defined(__ARM_EABI__) || !defined(USE_IRAM) - bl __div0 -#else - mov lr, pc - bx r3 -#endif - .size udiv32_arm, . - udiv32_arm |