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Diffstat (limited to 'lib/libc/sparc64/fpu/fpu_emu.h')
| -rw-r--r-- | lib/libc/sparc64/fpu/fpu_emu.h | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/lib/libc/sparc64/fpu/fpu_emu.h b/lib/libc/sparc64/fpu/fpu_emu.h new file mode 100644 index 0000000..0d1d16d --- /dev/null +++ b/lib/libc/sparc64/fpu/fpu_emu.h @@ -0,0 +1,176 @@ +/* + * Copyright (c) 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * This software was developed by the Computer Systems Engineering group + * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and + * contributed to Berkeley. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * @(#)fpu_emu.h 8.1 (Berkeley) 6/11/93 + * $NetBSD: fpu_emu.h,v 1.4 2000/08/03 18:32:07 eeh Exp $ + * $FreeBSD$ + */ + +/* + * Floating point emulator (tailored for SPARC, but structurally + * machine-independent). + * + * Floating point numbers are carried around internally in an `expanded' + * or `unpacked' form consisting of: + * - sign + * - unbiased exponent + * - mantissa (`1.' + 112-bit fraction + guard + round) + * - sticky bit + * Any implied `1' bit is inserted, giving a 113-bit mantissa that is + * always nonzero. Additional low-order `guard' and `round' bits are + * scrunched in, making the entire mantissa 115 bits long. This is divided + * into four 32-bit words, with `spare' bits left over in the upper part + * of the top word (the high bits of fp_mant[0]). An internal `exploded' + * number is thus kept within the half-open interval [1.0,2.0) (but see + * the `number classes' below). This holds even for denormalized numbers: + * when we explode an external denorm, we normalize it, introducing low-order + * zero bits, so that the rest of the code always sees normalized values. + * + * Note that a number of our algorithms use the `spare' bits at the top. + * The most demanding algorithm---the one for sqrt---depends on two such + * bits, so that it can represent values up to (but not including) 8.0, + * and then it needs a carry on top of that, so that we need three `spares'. + * + * The sticky-word is 32 bits so that we can use `OR' operators to goosh + * whole words from the mantissa into it. + * + * All operations are done in this internal extended precision. According + * to Hennesey & Patterson, Appendix A, rounding can be repeated---that is, + * it is OK to do a+b in extended precision and then round the result to + * single precision---provided single, double, and extended precisions are + * `far enough apart' (they always are), but we will try to avoid any such + * extra work where possible. + */ + +#ifndef _SPARC64_FPU_FPU_EMU_H_ +#define _SPARC64_FPU_FPU_EMU_H_ + +#include "fpu_reg.h" + +struct fpn { + int fp_class; /* see below */ + int fp_sign; /* 0 => positive, 1 => negative */ + int fp_exp; /* exponent (unbiased) */ + int fp_sticky; /* nonzero bits lost at right end */ + u_int fp_mant[4]; /* 115-bit mantissa */ +}; + +#define FP_NMANT 115 /* total bits in mantissa (incl g,r) */ +#define FP_NG 2 /* number of low-order guard bits */ +#define FP_LG ((FP_NMANT - 1) & 31) /* log2(1.0) for fp_mant[0] */ +#define FP_LG2 ((FP_NMANT - 1) & 63) /* log2(1.0) for fp_mant[0] and fp_mant[1] */ +#define FP_QUIETBIT (1 << (FP_LG - 1)) /* Quiet bit in NaNs (0.5) */ +#define FP_1 (1 << FP_LG) /* 1.0 in fp_mant[0] */ +#define FP_2 (1 << (FP_LG + 1)) /* 2.0 in fp_mant[0] */ + +/* + * Number classes. Since zero, Inf, and NaN cannot be represented using + * the above layout, we distinguish these from other numbers via a class. + * In addition, to make computation easier and to follow Appendix N of + * the SPARC Version 8 standard, we give each kind of NaN a separate class. + */ +#define FPC_SNAN -2 /* signalling NaN (sign irrelevant) */ +#define FPC_QNAN -1 /* quiet NaN (sign irrelevant) */ +#define FPC_ZERO 0 /* zero (sign matters) */ +#define FPC_NUM 1 /* number (sign matters) */ +#define FPC_INF 2 /* infinity (sign matters) */ + +#define ISNAN(fp) ((fp)->fp_class < 0) +#define ISZERO(fp) ((fp)->fp_class == 0) +#define ISINF(fp) ((fp)->fp_class == FPC_INF) + +/* + * ORDER(x,y) `sorts' a pair of `fpn *'s so that the right operand (y) points + * to the `more significant' operand for our purposes. Appendix N says that + * the result of a computation involving two numbers are: + * + * If both are SNaN: operand 2, converted to Quiet + * If only one is SNaN: the SNaN operand, converted to Quiet + * If both are QNaN: operand 2 + * If only one is QNaN: the QNaN operand + * + * In addition, in operations with an Inf operand, the result is usually + * Inf. The class numbers are carefully arranged so that if + * (unsigned)class(op1) > (unsigned)class(op2) + * then op1 is the one we want; otherwise op2 is the one we want. + */ +#define ORDER(x, y) { \ + if ((u_int)(x)->fp_class > (u_int)(y)->fp_class) \ + SWAP(x, y); \ +} +#define SWAP(x, y) { \ + register struct fpn *swap; \ + swap = (x), (x) = (y), (y) = swap; \ +} + +/* + * Floating point operand types. FTYPE_LNG is syntethic (it does not occur in + * instructions). + */ +#define FTYPE_INT INSFP_i +#define FTYPE_SNG INSFP_s +#define FTYPE_DBL INSFP_d +#define FTYPE_EXT INSFP_q +#define FTYPE_LNG 4 + +/* + * Emulator state. + */ +struct fpemu { + u_long fe_fsr; /* fsr copy (modified during op) */ + int fe_cx; /* exceptions */ + int pad; /* align access to following fields */ + struct fpn fe_f1; /* operand 1 */ + struct fpn fe_f2; /* operand 2, if required */ + struct fpn fe_f3; /* available storage for result */ +}; + +/* + * Arithmetic functions. + * Each of these may modify its inputs (f1,f2) and/or the temporary. + * Each returns a pointer to the result and/or sets exceptions. + */ +#define __fpu_sub(fe) ((fe)->fe_f2.fp_sign ^= 1, __fpu_add(fe)) + +#ifdef FPU_DEBUG +#define FPE_INSN 0x1 +#define FPE_REG 0x2 +extern int __fpe_debug; +void __fpu_dumpfpn(struct fpn *); +#define DPRINTF(x, y) if (__fpe_debug & (x)) printf y +#define DUMPFPN(x, f) if (__fpe_debug & (x)) __fpu_dumpfpn((f)) +#else +#define DPRINTF(x, y) +#define DUMPFPN(x, f) +#endif + +#endif /* !_SPARC64_FPU_FPU_EXTERN_H_ */ |
