[unix-history] / .ref-BSD-4_3_Net_2 / usr / src / lib / libc / tahoe / fpe / cvtlf.s

/*
 * Copyright (c) 1986 Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Computer Consoles Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(SYSLIBC_SCCS) && !defined(lint)
	.asciz "@(#)cvtlf.s	1.3 (Berkeley) 6/1/90"
#endif /* SYSLIBC_SCCS and not lint */

#include <tahoemath/fp.h>
#include "DEFS.h"

XENTRY(cvtlf, R2|R3|R4|R5)
 #
 #Some initializations:
 #
	clrl	r1
	clrl	r4		# r4 - negative flag.
	clrl	r2		# r2 - exponent.
	movl	4(fp),r0	# fetch operand.
	movl	r0,r5		# need another copy.
	jeql	retzero		# return zero.
	jgtr	positive
	mnegl	r0,r0
	jvs	retmin		# return minimum integer.
	incl	r4		# remember it was negative.
	movl	r0,r5		# remember the negated value.
 #
 #Compute exponent:
 #
positive:
	ffs	r0,r1
	incl 	r1
	addl2	r1,r2
	shrl	r1,r0,r0
	jneq	positive	# look for more set bits.
 #
 #we have the exponent in r2.
 #
	movl	r5,r0		# r0 will hold the resulting f.p. number.
 #
 #Shift the fraction part to its proper place:
 #
	subl3	r2,$HID_POS,r3
	jlss	shiftr		# if less then zero we have to shift right.
	shll	r3,r0,r0	# else we shift left.
	jmp	shifted
shiftr:
	mnegl	r3,r3
	shrl	r3,r0,r0
shifted:
	andl2	$CLEARHID,r0	# clear the hidden bit.
	shal	$EXPSHIFT,r2,r2	# shift the exponent to its proper place.
	orl2	$EXPSIGN,r2	# set the exponent sign bit(to bias it).
	orl2	r2,r0		# combine exponent & fraction.
	bbc	$0,r4,sign_ok	# do we  have to set the sign bit?
	orl2	$SIGNBIT,r0	# yes...
sign_ok:
	ret

retzero:
	clrl 	r0
	ret

retmin:
 	movl	$0xd0000000,r0
	ret
Commit	Line	Data
1f0502d3 KB	1	/*
	2	* Copyright (c) 1986 Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* This code is derived from software contributed to Berkeley by
	6	* Computer Consoles Inc.
	7	*
c0567266 KB	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
	16	* 3. All advertising materials mentioning features or use of this software
	17	* must display the following acknowledgement:
	18	* This product includes software developed by the University of
	19	* California, Berkeley and its contributors.
	20	* 4. Neither the name of the University nor the names of its contributors
	21	* may be used to endorse or promote products derived from this software
	22	* without specific prior written permission.
	23	*
	24	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	* SUCH DAMAGE.
1f0502d3 KB	35	*/
	36
	37	#if defined(SYSLIBC_SCCS) && !defined(lint)
1c15e888	38	.asciz "@(#)cvtlf.s 1.3 (Berkeley) 6/1/90"
1f0502d3	39	#endif /* SYSLIBC_SCCS and not lint */
c13f0b2e SL	40
	41	#include <tahoemath/fp.h>
	42	#include "DEFS.h"
	43
	44	XENTRY(cvtlf, R2\|R3\|R4\|R5)
	45	#
	46	#Some initializations:
	47	#
	48	clrl r1
	49	clrl r4 # r4 - negative flag.
	50	clrl r2 # r2 - exponent.
	51	movl 4(fp),r0 # fetch operand.
	52	movl r0,r5 # need another copy.
	53	jeql retzero # return zero.
	54	jgtr positive
	55	mnegl r0,r0
	56	jvs retmin # return minimum integer.
	57	incl r4 # remember it was negative.
	58	movl r0,r5 # remember the negated value.
	59	#
	60	#Compute exponent:
	61	#
	62	positive:
	63	ffs r0,r1
	64	incl r1
	65	addl2 r1,r2
	66	shrl r1,r0,r0
	67	jneq positive # look for more set bits.
	68	#
	69	#we have the exponent in r2.
	70	#
	71	movl r5,r0 # r0 will hold the resulting f.p. number.
	72	#
	73	#Shift the fraction part to its proper place:
	74	#
	75	subl3 r2,$HID_POS,r3
	76	jlss shiftr # if less then zero we have to shift right.
	77	shll r3,r0,r0 # else we shift left.
	78	jmp shifted
	79	shiftr:
	80	mnegl r3,r3
	81	shrl r3,r0,r0
	82	shifted:
	83	andl2 $CLEARHID,r0 # clear the hidden bit.
	84	shal $EXPSHIFT,r2,r2 # shift the exponent to its proper place.
	85	orl2 $EXPSIGN,r2 # set the exponent sign bit(to bias it).
	86	orl2 r2,r0 # combine exponent & fraction.
	87	bbc $0,r4,sign_ok # do we have to set the sign bit?
	88	orl2 $SIGNBIT,r0 # yes...
	89	sign_ok:
	90	ret
	91
	92	retzero:
	93	clrl r0
	94	ret
	95
	96	retmin:
	97	movl $0xd0000000,r0
	98	ret
	99
	100
	101