229 lines
6.1 KiB
ArmAsm
229 lines
6.1 KiB
ArmAsm
/*
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* Copyright (c) 1985 Regents of the University of California.
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* All rights reserved.
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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 reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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.data
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.align 2
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;_sccsid:
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;.asciz "from: @(#)support.s 1.3 (Berkeley) 8/21/85; 5.5 (ucb.elefunt) 10/9/90"
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_rcsid:
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.asciz "$Id: support.S,v 1.1 1993/08/14 13:44:15 mycroft Exp $"
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/*
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* copysign(x,y),
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* logb(x),
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* scalb(x,N),
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* finite(x),
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* drem(x,y),
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* Coded in vax assembly language by K.C. Ng, 3/14/85.
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* Revised by K.C. Ng on 4/9/85.
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*/
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/*
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* double copysign(x,y)
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* double x,y;
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*/
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.globl _copysign
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.text
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.align 1
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_copysign:
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.word 0x4
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movq 4(ap),r0 # load x into r0
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bicw3 $0x807f,r0,r2 # mask off the exponent of x
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beql Lz # if zero or reserved op then return x
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bicw3 $0x7fff,12(ap),r2 # copy the sign bit of y into r2
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bicw2 $0x8000,r0 # replace x by |x|
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bisw2 r2,r0 # copy the sign bit of y to x
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Lz: ret
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/*
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* double logb(x)
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* double x;
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*/
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.globl _logb
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.text
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.align 1
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_logb:
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.word 0x0
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bicl3 $0xffff807f,4(ap),r0 # mask off the exponent of x
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beql Ln
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ashl $-7,r0,r0 # get the bias exponent
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subl2 $129,r0 # get the unbias exponent
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cvtld r0,r0 # return the answer in double
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ret
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Ln: movq 4(ap),r0 # r0:1 = x (zero or reserved op)
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bneq 1f # simply return if reserved op
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movq $0x0000fe00ffffcfff,r0 # -2147483647.0
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1: ret
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/*
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* long finite(x)
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* double x;
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*/
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.globl _finite
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.text
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.align 1
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_finite:
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.word 0x0000
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bicw3 $0x7f,4(ap),r0 # mask off the mantissa
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cmpw r0,$0x8000 # to see if x is the reserved op
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beql 1f # if so, return FALSE (0)
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movl $1,r0 # else return TRUE (1)
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ret
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1: clrl r0
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ret
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/*
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* double scalb(x,N)
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* double x; int N;
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*/
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.globl _scalb
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.set ERANGE,34
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.text
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.align 1
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_scalb:
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.word 0xc
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movq 4(ap),r0
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bicl3 $0xffff807f,r0,r3
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beql ret1 # 0 or reserved operand
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movl 12(ap),r2
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cmpl r2,$0x12c
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bgeq ovfl
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cmpl r2,$-0x12c
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bleq unfl
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ashl $7,r2,r2
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addl2 r2,r3
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bleq unfl
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cmpl r3,$0x8000
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bgeq ovfl
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addl2 r2,r0
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ret
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ovfl: pushl $ERANGE
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calls $1,_infnan # if it returns
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bicw3 $0x7fff,4(ap),r2 # get the sign of input arg
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bisw2 r2,r0 # re-attach the sign to r0/1
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ret
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unfl: movq $0,r0
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ret1: ret
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/*
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* DREM(X,Y)
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* RETURN X REM Y =X-N*Y, N=[X/Y] ROUNDED (ROUNDED TO EVEN IN THE HALF WAY CASE)
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* DOUBLE PRECISION (VAX D format 56 bits)
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* CODED IN VAX ASSEMBLY LANGUAGE BY K.C. NG, 4/8/85.
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*/
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.globl _drem
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.set EDOM,33
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.text
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.align 1
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_drem:
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.word 0xffc
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subl2 $12,sp
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movq 4(ap),r0 #r0=x
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movq 12(ap),r2 #r2=y
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jeql Rop #if y=0 then generate reserved op fault
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bicw3 $0x007f,r0,r4 #check if x is Rop
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cmpw r4,$0x8000
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jeql Ret #if x is Rop then return Rop
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bicl3 $0x007f,r2,r4 #check if y is Rop
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cmpw r4,$0x8000
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jeql Ret #if y is Rop then return Rop
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bicw2 $0x8000,r2 #y := |y|
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movw $0,-4(fp) #-4(fp) = nx := 0
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cmpw r2,$0x1c80 #yexp ? 57
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bgtr C1 #if yexp > 57 goto C1
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addw2 $0x1c80,r2 #scale up y by 2**57
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movw $0x1c80,-4(fp) #nx := 57 (exponent field)
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C1:
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movw -4(fp),-8(fp) #-8(fp) = nf := nx
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bicw3 $0x7fff,r0,-12(fp) #-12(fp) = sign of x
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bicw2 $0x8000,r0 #x := |x|
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movq r2,r10 #y1 := y
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bicl2 $0xffff07ff,r11 #clear the last 27 bits of y1
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loop:
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cmpd r0,r2 #x ? y
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bleq E1 #if x <= y goto E1
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/* begin argument reduction */
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movq r2,r4 #t =y
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movq r10,r6 #t1=y1
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bicw3 $0x807f,r0,r8 #xexp= exponent of x
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bicw3 $0x807f,r2,r9 #yexp= exponent fo y
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subw2 r9,r8 #xexp-yexp
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subw2 $0x0c80,r8 #k=xexp-yexp-25(exponent bit field)
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blss C2 #if k<0 goto C2
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addw2 r8,r4 #t +=k
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addw2 r8,r6 #t1+=k, scale up t and t1
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C2:
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divd3 r4,r0,r8 #x/t
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cvtdl r8,r8 #n=[x/t] truncated
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cvtld r8,r8 #float(n)
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subd2 r6,r4 #t:=t-t1
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muld2 r8,r4 #n*(t-t1)
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muld2 r8,r6 #n*t1
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subd2 r6,r0 #x-n*t1
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subd2 r4,r0 #(x-n*t1)-n*(t-t1)
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brb loop
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E1:
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movw -4(fp),r6 #r6=nx
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beql C3 #if nx=0 goto C3
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addw2 r6,r0 #x:=x*2**57 scale up x by nx
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movw $0,-4(fp) #clear nx
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brb loop
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C3:
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movq r2,r4 #r4 = y
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subw2 $0x80,r4 #r4 = y/2
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cmpd r0,r4 #x:y/2
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blss E2 #if x < y/2 goto E2
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bgtr C4 #if x > y/2 goto C4
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cvtdl r8,r8 #ifix(float(n))
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blbc r8,E2 #if the last bit is zero, goto E2
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C4:
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subd2 r2,r0 #x-y
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E2:
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xorw2 -12(fp),r0 #x^sign (exclusive or)
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movw -8(fp),r6 #r6=nf
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bicw3 $0x807f,r0,r8 #r8=exponent of x
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bicw2 $0x7f80,r0 #clear the exponent of x
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subw2 r6,r8 #r8=xexp-nf
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bgtr C5 #if xexp-nf is positive goto C5
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movw $0,r8 #clear r8
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movq $0,r0 #x underflow to zero
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C5:
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bisw2 r8,r0 #put r8 into x's exponent field
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ret
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Rop: #Reserved operand
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pushl $EDOM
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calls $1,_infnan #generate reserved op fault
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ret
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Ret:
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movq $0x8000,r0 #propagate reserved op
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ret
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