^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /* IEEE754 floating point arithmetic
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * single precision
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * MIPS floating point support
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * Copyright (C) 1994-2000 Algorithmics Ltd.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * Copyright (C) 2017 Imagination Technologies, Ltd.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) * Author: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include "ieee754sp.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) union ieee754sp ieee754sp_rint(union ieee754sp x)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) union ieee754sp ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) u32 residue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) int sticky;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) int round;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) int odd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) COMPXDP; /* <-- DP needed for 64-bit mantissa tmp */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) ieee754_clearcx();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) EXPLODEXSP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) FLUSHXSP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) if (xc == IEEE754_CLASS_SNAN)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) return ieee754sp_nanxcpt(x);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) if ((xc == IEEE754_CLASS_QNAN) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) (xc == IEEE754_CLASS_INF) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) (xc == IEEE754_CLASS_ZERO))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) return x;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) if (xe >= SP_FBITS)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) return x;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) if (xe < -1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) residue = xm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) round = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) sticky = residue != 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) xm = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) residue = xm << (xe + 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) residue <<= 31 - SP_FBITS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) round = (residue >> 31) != 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) sticky = (residue << 1) != 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) xm >>= SP_FBITS - xe;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) odd = (xm & 0x1) != 0x0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) switch (ieee754_csr.rm) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) case FPU_CSR_RN: /* toward nearest */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) if (round && (sticky || odd))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) xm++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) case FPU_CSR_RZ: /* toward zero */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) case FPU_CSR_RU: /* toward +infinity */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) if ((round || sticky) && !xs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) xm++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) case FPU_CSR_RD: /* toward -infinity */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) if ((round || sticky) && xs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) xm++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) if (round || sticky)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) ieee754_setcx(IEEE754_INEXACT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) ret = ieee754sp_flong(xm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) SPSIGN(ret) = xs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) }