187 lines
4.8 KiB
ArmAsm
187 lines
4.8 KiB
ArmAsm
.file "reg_u_mul.S"
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/*
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* reg_u_mul.S
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*
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* Core multiplication routine
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*
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*
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* Copyright (C) 1992, 1993 W. Metzenthen, 22 Parker St, Ormond,
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* Vic 3163, Australia.
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* E-mail apm233m@vaxc.cc.monash.edu.au
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* All rights reserved.
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*
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* This copyright notice covers the redistribution and use of the
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* FPU emulator developed by W. Metzenthen. It covers only its use
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* in the 386BSD operating system. Any other use is not permitted
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* under this copyright.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must include information specifying
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* that source code for the emulator is freely available and include
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* either:
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* a) an offer to provide the source code for a nominal distribution
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* fee, or
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* b) list at least two alternative methods whereby the source
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* can be obtained, e.g. a publically accessible bulletin board
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* and an anonymous ftp site from which the software can be
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* downloaded.
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* 3. All advertising materials specifically mentioning features or use of
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* this emulator must acknowledge that it was developed by W. Metzenthen.
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* 4. The name of W. Metzenthen may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* W. METZENTHEN BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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/*---------------------------------------------------------------------------+
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| Basic multiplication routine. |
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| Does not check the resulting exponent for overflow/underflow |
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| |
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| reg_u_mul(FPU_REG *a, FPU_REG *b, FPU_REG *c, unsigned int cw); |
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| Internal working is at approx 128 bits. |
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| Result is rounded to nearest 53 or 64 bits, using "nearest or even". |
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+---------------------------------------------------------------------------*/
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#include "exception.h"
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#include "fpu_asm.h"
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#include "control_w.h"
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.data
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.align 2,0
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accum_0:
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.long 0
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accum_1:
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.long 0
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.text
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.align 2,144
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.globl _reg_u_mul
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_reg_u_mul:
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pushl %ebp
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movl %esp,%ebp
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pushl %esi
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pushl %edi
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pushl %ebx
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movl PARAM1,%esi
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movl PARAM2,%edi
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#ifdef PARANOID
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testl $0x80000000,SIGH(%esi)
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jz L_bugged
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testl $0x80000000,SIGH(%edi)
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jz L_bugged
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#endif PARANOID
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#ifdef DENORM_OPERAND
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movl EXP(%esi),%eax
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cmpl EXP_UNDER,%eax
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jg xOp1_not_denorm
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call _denormal_operand
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orl %eax,%eax
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jnz FPU_Arith_exit
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xOp1_not_denorm:
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movl EXP(%edi),%eax
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cmpl EXP_UNDER,%eax
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jg xOp2_not_denorm
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call _denormal_operand
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orl %eax,%eax
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jnz FPU_Arith_exit
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xOp2_not_denorm:
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#endif DENORM_OPERAND
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xorl %ecx,%ecx
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xorl %ebx,%ebx
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movl SIGL(%esi),%eax
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mull SIGL(%edi)
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movl %eax,accum_0
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movl %edx,accum_1
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movl SIGL(%esi),%eax
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mull SIGH(%edi)
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addl %eax,accum_1
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adcl %edx,%ebx
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/* adcl $0,%ecx *//* overflow here is not possible */
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movl SIGH(%esi),%eax
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mull SIGL(%edi)
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addl %eax,accum_1
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adcl %edx,%ebx
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adcl $0,%ecx
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movl SIGH(%esi),%eax
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mull SIGH(%edi)
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addl %eax,%ebx
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adcl %edx,%ecx
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movl EXP(%esi),%eax /* Compute the exponent */
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addl EXP(%edi),%eax
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subl EXP_BIAS-1,%eax
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/* Have now finished with the sources */
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movl PARAM3,%edi /* Point to the destination */
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movl %eax,EXP(%edi)
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/* Now make sure that the result is normalized */
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testl $0x80000000,%ecx
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jnz LResult_Normalised
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/* Normalize by shifting left one bit */
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shll $1,accum_0
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rcll $1,accum_1
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rcll $1,%ebx
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rcll $1,%ecx
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decl EXP(%edi)
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LResult_Normalised:
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movl accum_0,%eax
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movl accum_1,%edx
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orl %eax,%eax
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jz L_extent_zero
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orl $1,%edx
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L_extent_zero:
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movl %ecx,%eax
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jmp FPU_round
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#ifdef PARANOID
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L_bugged:
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pushl EX_INTERNAL|0x205
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call EXCEPTION
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pop %ebx
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jmp L_exit
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L_exit:
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popl %ebx
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popl %edi
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popl %esi
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leave
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ret
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#endif PARANOID
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