n_support.S revision 1.5
1 /* $NetBSD: n_support.S,v 1.5 2002/06/23 21:55:12 matt 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. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by the University of 17 * California, Berkeley and its contributors. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)support.s 8.1 (Berkeley) 6/4/93 35 */ 36 #include <machine/asm.h> 37 38 .text 39 _sccsid: 40 .asciz "@(#)support.s\t1.3 (Berkeley) 8/21/85; 8.1 (ucb.elefunt) 6/4/93" 41 42 /* 43 * copysign(x,y), 44 * logb(x), 45 * scalb(x,N), 46 * finite(x), 47 * drem(x,y), 48 * Coded in vax assembly language by K.C. Ng, 3/14/85. 49 * Revised by K.C. Ng on 4/9/85. 50 */ 51 52 /* 53 * double copysign(double x,double y) 54 */ 55 56 ENTRY(copysign, 0) 57 movq 4(%ap),%r0 # load x into %r0 58 bicw3 $0x807f,%r0,%r2 # mask off the exponent of x 59 beql Lz # if zero or reserved op then return x 60 bicw3 $0x7fff,12(%ap),%r2 # copy the sign bit of y into %r2 61 bicw2 $0x8000,%r0 # replace x by |x| 62 bisw2 %r2,%r0 # copy the sign bit of y to x 63 Lz: ret 64 65 /* 66 * double logb(double x); 67 */ 68 ENTRY(logb, 0) 69 bicl3 $0xffff807f,4(%ap),%r0 # mask off the exponent of x 70 beql Ln 71 ashl $-7,%r0,%r0 # get the bias exponent 72 subl2 $129,%r0 # get the unbias exponent 73 cvtld %r0,%r0 # return the answer in double 74 ret 75 Ln: movq 4(%ap),%r0 # %r0:1 = x (zero or reserved op) 76 bneq 1f # simply return if reserved op 77 movq $0x0000fe00ffffcfff,%r0 # -2147483647.0 78 1: ret 79 80 /* 81 * long finite(double x); 82 */ 83 #ifndef __GFLOAT__ 84 .globl finitef 85 finitef = finite 86 #endif 87 ENTRY(finite, 0) 88 bicw3 $0x7f,4(%ap),%r0 # mask off the mantissa 89 cmpw %r0,$0x8000 # to see if x is the reserved op 90 beql 1f # if so, return FALSE (0) 91 movl $1,%r0 # else return TRUE (1) 92 ret 93 1: clrl %r0 94 ret 95 96 /* int isnan(double x); 97 */ 98 #if 0 99 ENTRY(isnan, 0) 100 clrl %r0 101 ret 102 #endif 103 104 /* int isnanf(float x); 105 */ 106 ENTRY(isnanf, 0) 107 clrl %r0 108 ret 109 110 /* 111 * double scalb(x,N) 112 * double x; double N; 113 */ 114 .set ERANGE,34 115 116 ENTRY(scalb, 0) 117 movq 4(%ap),%r0 118 bicl3 $0xffff807f,%r0,%r3 119 beql ret1 # 0 or reserved operand 120 movq 12(%ap),%r4 121 cvtdl %r4, %r2 122 cmpl %r2,$0x12c 123 bgeq ovfl 124 cmpl %r2,$-0x12c 125 bleq unfl 126 ashl $7,%r2,%r2 127 addl2 %r2,%r3 128 bleq unfl 129 cmpl %r3,$0x8000 130 bgeq ovfl 131 addl2 %r2,%r0 132 ret 133 ovfl: pushl $ERANGE 134 calls $1,_C_LABEL(infnan) # if it returns 135 bicw3 $0x7fff,4(%ap),%r2 # get the sign of input arg 136 bisw2 %r2,%r0 # re-attach the sign to %r0/1 137 ret 138 unfl: movq $0,%r0 139 ret1: ret 140 141 /* 142 * DREM(X,Y) 143 * RETURN X REM Y =X-N*Y, N=[X/Y] ROUNDED (ROUNDED TO EVEN IN THE HALF WAY CASE) 144 * DOUBLE PRECISION (VAX D format 56 bits) 145 * CODED IN VAX ASSEMBLY LANGUAGE BY K.C. NG, 4/8/85. 146 */ 147 .set EDOM,33 148 149 ENTRY(drem, 0x0fc0) 150 subl2 $12,%sp 151 movq 4(%ap),%r0 #%r0=x 152 movq 12(%ap),%r2 #%r2=y 153 jeql Rop #if y=0 then generate reserved op fault 154 bicw3 $0x007f,%r0,%r4 #check if x is Rop 155 cmpw %r4,$0x8000 156 jeql Ret #if x is Rop then return Rop 157 bicl3 $0x007f,%r2,%r4 #check if y is Rop 158 cmpw %r4,$0x8000 159 jeql Ret #if y is Rop then return Rop 160 bicw2 $0x8000,%r2 #y := |y| 161 movw $0,-4(%fp) #-4(%fp) = nx := 0 162 cmpw %r2,$0x1c80 #yexp ? 57 163 bgtr C1 #if yexp > 57 goto C1 164 addw2 $0x1c80,%r2 #scale up y by 2**57 165 movw $0x1c80,-4(%fp) #nx := 57 (exponent field) 166 C1: 167 movw -4(%fp),-8(%fp) #-8(%fp) = nf := nx 168 bicw3 $0x7fff,%r0,-12(%fp) #-12(%fp) = sign of x 169 bicw2 $0x8000,%r0 #x := |x| 170 movq %r2,%r10 #y1 := y 171 bicl2 $0xffff07ff,%r11 #clear the last 27 bits of y1 172 loop: 173 cmpd %r0,%r2 #x ? y 174 bleq E1 #if x <= y goto E1 175 /* begin argument reduction */ 176 movq %r2,%r4 #t =y 177 movq %r10,%r6 #t1=y1 178 bicw3 $0x807f,%r0,%r8 #xexp= exponent of x 179 bicw3 $0x807f,%r2,%r9 #yexp= exponent fo y 180 subw2 %r9,%r8 #xexp-yexp 181 subw2 $0x0c80,%r8 #k=xexp-yexp-25(exponent bit field) 182 blss C2 #if k<0 goto C2 183 addw2 %r8,%r4 #t +=k 184 addw2 %r8,%r6 #t1+=k, scale up t and t1 185 C2: 186 divd3 %r4,%r0,%r8 #x/t 187 cvtdl %r8,%r8 #n=[x/t] truncated 188 cvtld %r8,%r8 #float(n) 189 subd2 %r6,%r4 #t:=t-t1 190 muld2 %r8,%r4 #n*(t-t1) 191 muld2 %r8,%r6 #n*t1 192 subd2 %r6,%r0 #x-n*t1 193 subd2 %r4,%r0 #(x-n*t1)-n*(t-t1) 194 jbr loop 195 E1: 196 movw -4(%fp),%r6 #%r6=nx 197 beql C3 #if nx=0 goto C3 198 addw2 %r6,%r0 #x:=x*2**57 scale up x by nx 199 movw $0,-4(%fp) #clear nx 200 jbr loop 201 C3: 202 movq %r2,%r4 #%r4 = y 203 subw2 $0x80,%r4 #%r4 = y/2 204 cmpd %r0,%r4 #x:y/2 205 blss E2 #if x < y/2 goto E2 206 bgtr C4 #if x > y/2 goto C4 207 cvtdl %r8,%r8 #ifix(float(n)) 208 blbc %r8,E2 #if the last bit is zero, goto E2 209 C4: 210 subd2 %r2,%r0 #x-y 211 E2: 212 xorw2 -12(%fp),%r0 #x^sign (exclusive or) 213 movw -8(%fp),%r6 #%r6=nf 214 bicw3 $0x807f,%r0,%r8 #%r8=exponent of x 215 bicw2 $0x7f80,%r0 #clear the exponent of x 216 subw2 %r6,%r8 #%r8=xexp-nf 217 bgtr C5 #if xexp-nf is positive goto C5 218 movw $0,%r8 #clear %r8 219 movq $0,%r0 #x underflow to zero 220 C5: 221 bisw2 %r8,%r0 /* put %r8 into x's exponent field */ 222 ret 223 Rop: #Reserved operand 224 pushl $EDOM 225 calls $1,_C_LABEL(infnan) #generate reserved op fault 226 ret 227 Ret: 228 movq $0x8000,%r0 #propagate reserved op 229 ret 230
Indexes created Tue Sep 30 20:09:53 GMT 2025