1 /*- 2 * Copyright (c) 1985 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Computer Consoles Inc. 7 * 8 * %sccs.include.redist.c% 9 * 10 * @(#)FP.h 7.1 (Berkeley) 12/06/90 11 */ 12 13 /* 14 * General definitions of the floating point stuff on Power 6/32. 15 * The floating point format definition is: 16 * 17 * S (exp-128) 18 * (-1) * 2 * F 19 * 20 * Where exp is the exponent field and F is the binary 21 * mantissa following it, including the hidden bit. 22 * The hidden bit actually is 1/2, so F is known to 23 * satisfy the range: 24 * 1/2 <= F < 1 25 */ 26 27 typedef struct { 28 unsigned sign:1; 29 unsigned exponent:8; 30 unsigned mantissa:23; 31 } sp_format; 32 33 typedef struct { 34 unsigned sign:1; 35 unsigned exponent:8; 36 unsigned mantissa:23; 37 unsigned mantissa_lst; 38 } dp_format; 39 40 #define EXP_BIAS 128 /* Exponent bias */ 41 #define SIGN_BIT 0x80000000 /* S bit mask */ 42