/* (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands. See the copyright notice in the ACK home directory, in the file "Copyright". */ /* $Header: /cvsup/minix/src/lib/float/sub_ext.c,v 1.1.1.1 2005/04/21 14:56:11 beng Exp $ */ /* SUBTRACT 2 EXTENDED FORMAT NUMBERS */ #include "FP_types.h" void sub_ext(e1,e2) EXTEND *e1,*e2; { if ((e2->m1 | e2->m2) == 0L) { return; } if ((e1->m1 | e1->m2) == 0L) { *e1 = *e2; e1->sign = e2->sign ? 0 : 1; return; } sft_ext(e1, e2); if (e1->sign != e2->sign) { /* e1 - e2 = e1 + (-e2) */ if (b64_add(&e1->mantissa,&e2->mantissa)) { /* addition carry */ b64_rsft(&e1->mantissa); /* shift mantissa one bit RIGHT */ e1->m1 |= 0x80000000L; /* set max bit */ e1->exp++; /* increase the exponent */ } } else if (e2->m1 > e1->m1 || (e2->m1 == e1->m1 && e2->m2 > e1->m2)) { /* abs(e2) > abs(e1) */ if (e1->m2 > e2->m2) { e2->m1 -= 1; /* carry in */ } e2->m1 -= e1->m1; e2->m2 -= e1->m2; *e1 = *e2; e1->sign = e2->sign ? 0 : 1; } else { if (e2->m2 > e1->m2) e1->m1 -= 1; /* carry in */ e1->m1 -= e2->m1; e1->m2 -= e2->m2; } nrm_ext(e1); }