177 lines
4.5 KiB
ArmAsm
177 lines
4.5 KiB
ArmAsm
/*
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* reg_norm.s
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*
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* Normalize the value in a FPU_REG.
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*
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* Call from C as:
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* void normalize(FPU_REG *n)
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*
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* void normalize_nuo(FPU_REG *n)
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*
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*
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* Copyright (C) 1992,1993,1994
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* W. Metzenthen, 22 Parker St, Ormond, Vic 3163,
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* Australia. E-mail billm@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, FreeBSD and NetBSD operating systems. Any other
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* use is not permitted 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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* The purpose of this copyright, based upon the Berkeley copyright, is to
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* ensure that the covered software remains freely available to everyone.
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*
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* The software (with necessary differences) is also available, but under
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* the terms of the GNU copyleft, for the Linux operating system and for
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* the djgpp ms-dos extender.
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*
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* W. Metzenthen June 1994.
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*
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*
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* $FreeBSD$
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*
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*/
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#include <gnu/i386/fpemul/fpu_asm.h>
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.text
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ENTRY(normalize)
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pushl %ebp
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movl %esp,%ebp
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pushl %ebx
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movl PARAM1,%ebx
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movl SIGH(%ebx),%edx
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movl SIGL(%ebx),%eax
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orl %edx,%edx /* ms bits */
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js L_done /* Already normalized */
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jnz L_shift_1 /* Shift left 1 - 31 bits */
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orl %eax,%eax
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jz L_zero /* The contents are zero */
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/* L_shift_32: */
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movl %eax,%edx
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xorl %eax,%eax
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subl $32,EXP(%ebx) /* This can cause an underflow */
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/* We need to shift left by 1 - 31 bits */
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L_shift_1:
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bsrl %edx,%ecx /* get the required shift in %ecx */
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subl $31,%ecx
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negl %ecx
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shld %cl,%eax,%edx
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shl %cl,%eax
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subl %ecx,EXP(%ebx) /* This can cause an underflow */
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movl %edx,SIGH(%ebx)
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movl %eax,SIGL(%ebx)
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L_done:
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cmpl EXP_OVER,EXP(%ebx)
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jge L_overflow
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cmpl EXP_UNDER,EXP(%ebx)
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jle L_underflow
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L_exit:
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popl %ebx
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leave
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ret
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L_zero:
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movl EXP_UNDER,EXP(%ebx)
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movb TW_Zero,TAG(%ebx)
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jmp L_exit
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L_underflow:
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push %ebx
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call _arith_underflow
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pop %ebx
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jmp L_exit
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L_overflow:
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push %ebx
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call _arith_overflow
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pop %ebx
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jmp L_exit
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/* Normalise without reporting underflow or overflow */
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ENTRY(normalize_nuo)
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pushl %ebp
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movl %esp,%ebp
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pushl %ebx
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movl PARAM1,%ebx
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movl SIGH(%ebx),%edx
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movl SIGL(%ebx),%eax
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orl %edx,%edx /* ms bits */
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js L_exit /* Already normalized */
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jnz L_nuo_shift_1 /* Shift left 1 - 31 bits */
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orl %eax,%eax
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jz L_zero /* The contents are zero */
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/* L_nuo_shift_32: */
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movl %eax,%edx
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xorl %eax,%eax
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subl $32,EXP(%ebx) /* This can cause an underflow */
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/* We need to shift left by 1 - 31 bits */
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L_nuo_shift_1:
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bsrl %edx,%ecx /* get the required shift in %ecx */
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subl $31,%ecx
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negl %ecx
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shld %cl,%eax,%edx
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shl %cl,%eax
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subl %ecx,EXP(%ebx) /* This can cause an underflow */
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movl %edx,SIGH(%ebx)
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movl %eax,SIGL(%ebx)
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jmp L_exit
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