1/* $NetBSD: n_support.S,v 1.7 2014/02/03 21:22:21 martin Exp $ */ 2/* 3 * Copyright (c) 1985, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * @(#)support.s 8.1 (Berkeley) 6/4/93 31 */ 32#include <machine/asm.h> 33 34WEAK_ALIAS(logbl,logb) 35 36 .text 37_sccsid: 38 .asciz "@(#)support.s\t1.3 (Berkeley) 8/21/85; 8.1 (ucb.elefunt) 6/4/93" 39 40/* 41 * copysign(x,y), 42 * logb(x), 43 * scalb(x,N), 44 * finite(x), 45 * drem(x,y), 46 * Coded in vax assembly language by K.C. Ng, 3/14/85. 47 * Revised by K.C. Ng on 4/9/85. 48 */ 49 50/* 51 * double copysign(double x,double y) 52 */ 53 54ENTRY(copysign, 0) 55 movq 4(%ap),%r0 # load x into %r0 56 bicw3 $0x807f,%r0,%r2 # mask off the exponent of x 57 beql Lz # if zero or reserved op then return x 58 bicw3 $0x7fff,12(%ap),%r2 # copy the sign bit of y into %r2 59 bicw2 $0x8000,%r0 # replace x by |x| 60 bisw2 %r2,%r0 # copy the sign bit of y to x 61Lz: ret 62 63/* 64 * float logbf(float x); 65 */ 66ENTRY(logbf, 0) 67 cvtfd 4(%ap),-(%sp) 68 calls $2,_C_LABEL(logb) 69 cvtdf %r0,%r0 70 ret 71 72/* 73 * double logb(double x); 74 */ 75ENTRY(logb, 0) 76 bicl3 $0xffff807f,4(%ap),%r0 # mask off the exponent of x 77 beql Ln 78 ashl $-7,%r0,%r0 # get the bias exponent 79 subl2 $129,%r0 # get the unbias exponent 80 cvtld %r0,%r0 # return the answer in double 81 ret 82Ln: movq 4(%ap),%r0 # %r0:1 = x (zero or reserved op) 83 bneq 1f # simply return if reserved op 84 movq $0x0000fe00ffffcfff,%r0 # -2147483647.0 851: ret 86 87/* 88 * long finite(double x); 89 */ 90#ifndef __GFLOAT__ 91 .globl finitef 92finitef = finite 93#endif 94ENTRY(finite, 0) 95 bicw3 $0x7f,4(%ap),%r0 # mask off the mantissa 96 cmpw %r0,$0x8000 # to see if x is the reserved op 97 beql 1f # if so, return FALSE (0) 98 movl $1,%r0 # else return TRUE (1) 99 ret 1001: clrl %r0 101 ret 102 103/* int isnan(double x); 104 */ 105#if 0 106ENTRY(isnan, 0) 107 clrl %r0 108 ret 109#endif 110 111/* int isnanf(float x); 112 */ 113ENTRY(isnanf, 0) 114 clrl %r0 115 ret 116 117/* 118 * double scalb(x,N) 119 * double x; double N; 120 */ 121 .set ERANGE,34 122 123ENTRY(scalb, 0) 124 movq 4(%ap),%r0 125 bicl3 $0xffff807f,%r0,%r3 126 beql ret1 # 0 or reserved operand 127 movq 12(%ap),%r4 128 cvtdl %r4, %r2 129 cmpl %r2,$0x12c 130 bgeq ovfl 131 cmpl %r2,$-0x12c 132 bleq unfl 133 ashl $7,%r2,%r2 134 addl2 %r2,%r3 135 bleq unfl 136 cmpl %r3,$0x8000 137 bgeq ovfl 138 addl2 %r2,%r0 139 ret 140ovfl: pushl $ERANGE 141 calls $1,_C_LABEL(infnan) # if it returns 142 bicw3 $0x7fff,4(%ap),%r2 # get the sign of input arg 143 bisw2 %r2,%r0 # re-attach the sign to %r0/1 144 ret 145unfl: movq $0,%r0 146ret1: ret 147 148/* 149 * DREM(X,Y) 150 * RETURN X REM Y =X-N*Y, N=[X/Y] ROUNDED (ROUNDED TO EVEN IN THE HALF WAY CASE) 151 * DOUBLE PRECISION (VAX D format 56 bits) 152 * CODED IN VAX ASSEMBLY LANGUAGE BY K.C. NG, 4/8/85. 153 */ 154 .set EDOM,33 155 156ENTRY(drem, 0x0fc0) 157 subl2 $12,%sp 158 movq 4(%ap),%r0 #%r0=x 159 movq 12(%ap),%r2 #%r2=y 160 jeql Rop #if y=0 then generate reserved op fault 161 bicw3 $0x007f,%r0,%r4 #check if x is Rop 162 cmpw %r4,$0x8000 163 jeql Ret #if x is Rop then return Rop 164 bicl3 $0x007f,%r2,%r4 #check if y is Rop 165 cmpw %r4,$0x8000 166 jeql Ret #if y is Rop then return Rop 167 bicw2 $0x8000,%r2 #y := |y| 168 movw $0,-4(%fp) #-4(%fp) = nx := 0 169 cmpw %r2,$0x1c80 #yexp ? 57 170 bgtr C1 #if yexp > 57 goto C1 171 addw2 $0x1c80,%r2 #scale up y by 2**57 172 movw $0x1c80,-4(%fp) #nx := 57 (exponent field) 173C1: 174 movw -4(%fp),-8(%fp) #-8(%fp) = nf := nx 175 bicw3 $0x7fff,%r0,-12(%fp) #-12(%fp) = sign of x 176 bicw2 $0x8000,%r0 #x := |x| 177 movq %r2,%r10 #y1 := y 178 bicl2 $0xffff07ff,%r11 #clear the last 27 bits of y1 179loop: 180 cmpd %r0,%r2 #x ? y 181 bleq E1 #if x <= y goto E1 182 /* begin argument reduction */ 183 movq %r2,%r4 #t =y 184 movq %r10,%r6 #t1=y1 185 bicw3 $0x807f,%r0,%r8 #xexp= exponent of x 186 bicw3 $0x807f,%r2,%r9 #yexp= exponent fo y 187 subw2 %r9,%r8 #xexp-yexp 188 subw2 $0x0c80,%r8 #k=xexp-yexp-25(exponent bit field) 189 blss C2 #if k<0 goto C2 190 addw2 %r8,%r4 #t +=k 191 addw2 %r8,%r6 #t1+=k, scale up t and t1 192C2: 193 divd3 %r4,%r0,%r8 #x/t 194 cvtdl %r8,%r8 #n=[x/t] truncated 195 cvtld %r8,%r8 #float(n) 196 subd2 %r6,%r4 #t:=t-t1 197 muld2 %r8,%r4 #n*(t-t1) 198 muld2 %r8,%r6 #n*t1 199 subd2 %r6,%r0 #x-n*t1 200 subd2 %r4,%r0 #(x-n*t1)-n*(t-t1) 201 jbr loop 202E1: 203 movw -4(%fp),%r6 #%r6=nx 204 beql C3 #if nx=0 goto C3 205 addw2 %r6,%r0 #x:=x*2**57 scale up x by nx 206 movw $0,-4(%fp) #clear nx 207 jbr loop 208C3: 209 movq %r2,%r4 #%r4 = y 210 subw2 $0x80,%r4 #%r4 = y/2 211 cmpd %r0,%r4 #x:y/2 212 blss E2 #if x < y/2 goto E2 213 bgtr C4 #if x > y/2 goto C4 214 cvtdl %r8,%r8 #ifix(float(n)) 215 blbc %r8,E2 #if the last bit is zero, goto E2 216C4: 217 subd2 %r2,%r0 #x-y 218E2: 219 xorw2 -12(%fp),%r0 #x^sign (exclusive or) 220 movw -8(%fp),%r6 #%r6=nf 221 bicw3 $0x807f,%r0,%r8 #%r8=exponent of x 222 bicw2 $0x7f80,%r0 #clear the exponent of x 223 subw2 %r6,%r8 #%r8=xexp-nf 224 bgtr C5 #if xexp-nf is positive goto C5 225 movw $0,%r8 #clear %r8 226 movq $0,%r0 #x underflow to zero 227C5: 228 bisw2 %r8,%r0 /* put %r8 into x's exponent field */ 229 ret 230Rop: #Reserved operand 231 pushl $EDOM 232 calls $1,_C_LABEL(infnan) #generate reserved op fault 233 ret 234Ret: 235 movq $0x8000,%r0 #propagate reserved op 236 ret 237