cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

sp_fdp.c (1465B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* IEEE754 floating point arithmetic
      3 * single precision
      4 */
      5/*
      6 * MIPS floating point support
      7 * Copyright (C) 1994-2000 Algorithmics Ltd.
      8 */
      9
     10#include "ieee754sp.h"
     11#include "ieee754dp.h"
     12
     13static inline union ieee754sp ieee754sp_nan_fdp(int xs, u64 xm)
     14{
     15	return buildsp(xs, SP_EMAX + 1 + SP_EBIAS,
     16		       xm >> (DP_FBITS - SP_FBITS));
     17}
     18
     19union ieee754sp ieee754sp_fdp(union ieee754dp x)
     20{
     21	union ieee754sp y;
     22	u32 rm;
     23
     24	COMPXDP;
     25	COMPYSP;
     26
     27	EXPLODEXDP;
     28
     29	ieee754_clearcx();
     30
     31	FLUSHXDP;
     32
     33	switch (xc) {
     34	case IEEE754_CLASS_SNAN:
     35		x = ieee754dp_nanxcpt(x);
     36		EXPLODEXDP;
     37		fallthrough;
     38	case IEEE754_CLASS_QNAN:
     39		y = ieee754sp_nan_fdp(xs, xm);
     40		if (!ieee754_csr.nan2008) {
     41			EXPLODEYSP;
     42			if (!ieee754_class_nan(yc))
     43				y = ieee754sp_indef();
     44		}
     45		return y;
     46
     47	case IEEE754_CLASS_INF:
     48		return ieee754sp_inf(xs);
     49
     50	case IEEE754_CLASS_ZERO:
     51		return ieee754sp_zero(xs);
     52
     53	case IEEE754_CLASS_DNORM:
     54		/* can't possibly be sp representable */
     55		ieee754_setcx(IEEE754_UNDERFLOW);
     56		ieee754_setcx(IEEE754_INEXACT);
     57		if ((ieee754_csr.rm == FPU_CSR_RU && !xs) ||
     58				(ieee754_csr.rm == FPU_CSR_RD && xs))
     59			return ieee754sp_mind(xs);
     60		return ieee754sp_zero(xs);
     61
     62	case IEEE754_CLASS_NORM:
     63		break;
     64	}
     65
     66	/*
     67	 * Convert from DP_FBITS to SP_FBITS+3 with sticky right shift.
     68	 */
     69	rm = (xm >> (DP_FBITS - (SP_FBITS + 3))) |
     70	     ((xm << (64 - (DP_FBITS - (SP_FBITS + 3)))) != 0);
     71
     72	return ieee754sp_format(xs, xe, rm);
     73}