1 /*---------------------------------------------------------------------------+ 2 | reg_convert.c | 3 | | 4 | Convert register representation. | 5 | | 6 | Copyright (C) 1992,1993,1994,1996,1997 | 7 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia | 8 | E-mail billm@suburbia.net | 9 | | 10 | | 11 +---------------------------------------------------------------------------*/ 12 13 #include "exception.h" 14 #include "fpu_emu.h" 15 16 17 int FPU_to_exp16(FPU_REG const *a, FPU_REG *x) 18 { 19 int sign = getsign(a); 20 21 *(long long *)&(x->sigl) = *(const long long *)&(a->sigl); 22 23 /* Set up the exponent as a 16 bit quantity. */ 24 setexponent16(x, exponent(a)); 25 26 if ( exponent16(x) == EXP_UNDER ) 27 { 28 /* The number is a de-normal or pseudodenormal. */ 29 /* We only deal with the significand and exponent. */ 30 31 if (x->sigh & 0x80000000) 32 { 33 /* Is a pseudodenormal. */ 34 /* This is non-80486 behaviour because the number 35 loses its 'denormal' identity. */ 36 addexponent(x, 1); 37 } 38 else 39 { 40 /* Is a denormal. */ 41 addexponent(x, 1); 42 FPU_normalize_nuo(x); 43 } 44 } 45 46 if ( !(x->sigh & 0x80000000) ) 47 { 48 EXCEPTION(EX_INTERNAL | 0x180); 49 } 50 51 return sign; 52 } 53 54