69 lines
2.2 KiB
ArmAsm
69 lines
2.2 KiB
ArmAsm
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/*
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* Copyright (c) 1992 Helsinki University of Technology
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* HELSINKI UNIVERSITY OF TECHNOLOGY ALLOWS FREE USE OF THIS SOFTWARE IN
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* ITS "AS IS" CONDITION. HELSINKI UNIVERSITY OF TECHNOLOGY DISCLAIMS ANY
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* LIABILITY OF ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE
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* USE OF THIS SOFTWARE.
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*/
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/*
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* HISTORY
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* 29-Apr-92 Tero Kivinen (kivinen) at Helsinki University of Technology
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* Created.
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*
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* $Id: modf.s,v 1.1.1.1 1993/09/17 18:43:47 phil Exp $
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*/
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/*
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* double modf (value, iptr)
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* double value, *iptr;
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*
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* Modf returns the fractional part of "value",
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* and stores the integer part indirectly through "iptr".
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*/
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#include <machine/asm.h>
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ENTRY(modf)
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FRAME
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movl 8(fp),f0 /* value */
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movd 12(fp),r0 /* higher 32 bit of value */
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lshd -20,r0 /* extract exponent */
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andd 0x7ff,r0 /* 11 lower bits */
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cmpd r0,1023+30 /* compare if it's int part can fit in int */
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bgt modf_overflow /* nope else it's ok to truncld it to int*/
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truncld f0,r0 /* get integer part */
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movdl r0,f2 /* convert back to float */
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movl f2,0(16(fp)) /* move integer part to *iptr */
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subl f2,f0 /* return fract. part = value - *iptr */
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EMARF
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ret 0
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modf_overflow:
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subd 1023+20,r0 /* bias 1023, and upper part of
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floating point mantissa part */
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movqd -1,r2 /* generate mask to get fract. part */
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cmpd r0,32 /* if value > 2^52 (20+32) then all int part */
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bhi modf_all_ip
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negd r0,r0 /* shift right */
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lshd r0,r2 /* here */
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comd r2,r2 /* get fractional part complement mask */
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movd 8(fp),r1 /* get lower 32 bit of value */
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andd r2,r1 /* mask fractional part off leave ip part */
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movd r1,0(16(fp)) /* store ip part to *iptr */
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movd 12(fp),4(16(fp)) /* store other half to *iptr */
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subl 0(16(fp)),f0 /* return fract. part = value - *iptr */
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EMARF
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ret 0
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modf_all_ip:
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movl 8(fp),0(16(fp)) /* copy value to *iptr */
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movdl 0,f0 /* return 0 for fract. part */
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EMARF
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ret 0
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