1/* 2 * Copyright (c) 1988 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 * 17 * This code is derived from software contributed to Berkeley by 18 * Computer Consoles Inc. 19 */ 20 21#if defined(LIBC_SCCS) && !defined(lint) 22 .asciz "@(#)modf.s 1.4 (Berkeley) 06/27/88" 23#endif /* LIBC_SCCS and not lint */ 24 25/* 26 * double modf (value, iptr) 27 * double value, *iptr; 28 * 29 * Modf returns the fractional part of "value", 30 * and stores the integer part indirectly through "iptr". 31 * 32 * This version uses floating point (look in ../fpe for 33 * a much slower integer version). 34 */ 35 36#include "DEFS.h" 37 38ENTRY(modf, 0) 39 ldd 4(fp) # value 40 cvdl r2 # integerize 41 bvs 1f # did integer part overflow? 42 cvld r2 # integer part 43 std r0 44 std *12(fp) # *iptr = r2 45 ldd 4(fp) 46 subd r0 # value-(int)value 47 std r0 # return fraction 48 ret 491: 50 /* 51 * If the integer portion overflowed, mask out the fractional 52 * bits in the double word instead of cvdl-ing. 53 */ 54 ldd 4(fp) 55 std r0 # (r0,r1) = value 56 shrl $23,r0,r2 # extract sign,exponent of value 57 andl2 $255,r2 # exponent 58 subl2 $152,r2 # e-152 59 /* 60 * If it overflowed then value>=2^31 and e>=160 61 * so we mask only r1 (low bits of fraction), not r0 62 */ 63 mnegl $1,r3 64 shrl r2,r3,r3 # -1>>(e-152) is neg mask to clear fraction 65 mcoml r3,r3 # complement mask 66 andl2 r3,r1 # mask off truly fractional bits from fraction 67 ldd r0 # now (r0,r1) = integerized value 68 std *12(fp) # *iptr = integerized 69 ldd 4(fp) 70 subd r0 71 std r0 # return fraction 72 ret 73