134 lines
4.5 KiB
ArmAsm
134 lines
4.5 KiB
ArmAsm
# Copyright (c) 1985 Regents of the University of California.
|
|
# All rights reserved.
|
|
#
|
|
# 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.
|
|
#
|
|
.data
|
|
.align 2
|
|
;_sccsid:
|
|
;.asciz "from: @(#)cabs.s 1.2 (Berkeley) 8/21/85; 5.4 (ucb.elefunt) 10/9/90"
|
|
_rcsid:
|
|
.asciz "$Id: cabs.s,v 1.1 1993/08/14 13:44:09 mycroft Exp $"
|
|
|
|
# double precision complex absolute value
|
|
# CABS by W. Kahan, 9/7/80.
|
|
# Revised for reserved operands by E. LeBlanc, 8/18/82
|
|
# argument for complex absolute value by reference, *4(ap)
|
|
# argument for cabs and hypot (C fcns) by value, 4(ap)
|
|
# output is in r0:r1 (error less than 0.86 ulps)
|
|
|
|
.text
|
|
.align 1
|
|
.globl _cabs
|
|
.globl _hypot
|
|
.globl _z_abs
|
|
.globl libm$cdabs_r6
|
|
.globl libm$dsqrt_r5
|
|
|
|
# entry for c functions cabs and hypot
|
|
_cabs:
|
|
_hypot:
|
|
.word 0x807c # save r2-r6, enable floating overflow
|
|
movq 4(ap),r0 # r0:1 = x
|
|
movq 12(ap),r2 # r2:3 = y
|
|
jmp cabs2
|
|
# entry for Fortran use, call by: d = abs(z)
|
|
_z_abs:
|
|
.word 0x807c # save r2-r6, enable floating overflow
|
|
movl 4(ap),r2 # indirect addressing is necessary here
|
|
movq (r2)+,r0 # r0:1 = x
|
|
movq (r2),r2 # r2:3 = y
|
|
|
|
cabs2:
|
|
bicw3 $0x7f,r0,r4 # r4 has signed biased exp of x
|
|
cmpw $0x8000,r4
|
|
jeql return # x is a reserved operand, so return it
|
|
bicw3 $0x7f,r2,r5 # r5 has signed biased exp of y
|
|
cmpw $0x8000,r5
|
|
jneq cont # y isn't a reserved operand
|
|
movq r2,r0 # return y if it's reserved
|
|
ret
|
|
|
|
cont:
|
|
bsbb regs_set # r0:1 = dsqrt(x^2+y^2)/2^r6
|
|
addw2 r6,r0 # unscaled cdabs in r0:1
|
|
jvc return # unless it overflows
|
|
subw2 $0x80,r0 # halve r0 to get meaningful overflow
|
|
addd2 r0,r0 # overflow; r0 is half of true abs value
|
|
return:
|
|
ret
|
|
|
|
libm$cdabs_r6: # ENTRY POINT for cdsqrt
|
|
# calculates a scaled (factor in r6)
|
|
# complex absolute value
|
|
|
|
movq (r4)+,r0 # r0:r1 = x via indirect addressing
|
|
movq (r4),r2 # r2:r3 = y via indirect addressing
|
|
|
|
bicw3 $0x7f,r0,r5 # r5 has signed biased exp of x
|
|
cmpw $0x8000,r5
|
|
jeql cdreserved # x is a reserved operand
|
|
bicw3 $0x7f,r2,r5 # r5 has signed biased exp of y
|
|
cmpw $0x8000,r5
|
|
jneq regs_set # y isn't a reserved operand either?
|
|
|
|
cdreserved:
|
|
movl *4(ap),r4 # r4 -> (u,v), if x or y is reserved
|
|
movq r0,(r4)+ # copy u and v as is and return
|
|
movq r2,(r4) # (again addressing is indirect)
|
|
ret
|
|
|
|
regs_set:
|
|
bicw2 $0x8000,r0 # r0:r1 = dabs(x)
|
|
bicw2 $0x8000,r2 # r2:r3 = dabs(y)
|
|
cmpw r0,r2
|
|
jgeq ordered
|
|
movq r0,r4
|
|
movq r2,r0
|
|
movq r4,r2 # force y's exp <= x's exp
|
|
ordered:
|
|
bicw3 $0x7f,r0,r6 # r6 = exponent(x) + bias(129)
|
|
jeql retsb # if x = y = 0 then cdabs(x,y) = 0
|
|
subw2 $0x4780,r6 # r6 = exponent(x) - 14
|
|
subw2 r6,r0 # 2^14 <= scaled x < 2^15
|
|
bitw $0xff80,r2
|
|
jeql retsb # if y = 0 return dabs(x)
|
|
subw2 r6,r2
|
|
cmpw $0x3780,r2 # if scaled y < 2^-18
|
|
jgtr retsb # return dabs(x)
|
|
emodd r0,$0,r0,r4,r0 # r4 + r0:1 = scaled x^2
|
|
emodd r2,$0,r2,r5,r2 # r5 + r2:3 = scaled y^2
|
|
addd2 r2,r0
|
|
addl2 r5,r4
|
|
cvtld r4,r2
|
|
addd2 r2,r0 # r0:1 = scaled x^2 + y^2
|
|
jmp libm$dsqrt_r5 # r0:1 = dsqrt(x^2+y^2)/2^r6
|
|
retsb:
|
|
rsb # error < 0.86 ulp
|