/* ----------------------------------------------------------------------- * * * Copyright 1996-2018 The NASM Authors - All Rights Reserved * See the file AUTHORS included with the NASM distribution for * the specific copyright holders. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following * conditions are met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 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. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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. * * ----------------------------------------------------------------------- */ /* * float.c floating-point constant support for the Netwide Assembler */ #include "compiler.h" #include #include #include #include #include "nasm.h" #include "float.h" #include "error.h" /* * ----------------- * local variables * ----------------- */ static bool daz = false; /* denormals as zero */ static enum float_round rc = FLOAT_RC_NEAR; /* rounding control */ /* * ----------- * constants * ----------- */ /* "A limb is like a digit but bigger */ typedef uint32_t fp_limb; typedef uint64_t fp_2limb; #define LIMB_BITS 32 #define LIMB_BYTES (LIMB_BITS/8) #define LIMB_TOP_BIT ((fp_limb)1 << (LIMB_BITS-1)) #define LIMB_MASK ((fp_limb)(~0)) #define LIMB_ALL_BYTES ((fp_limb)0x01010101) #define LIMB_BYTE(x) ((x)*LIMB_ALL_BYTES) /* 112 bits + 64 bits for accuracy + 16 bits for rounding */ #define MANT_LIMBS 6 /* 52 digits fit in 176 bits because 10^53 > 2^176 > 10^52 */ #define MANT_DIGITS 52 /* the format and the argument list depend on MANT_LIMBS */ #define MANT_FMT "%08x_%08x_%08x_%08x_%08x_%08x" #define MANT_ARG SOME_ARG(mant, 0) #define SOME_ARG(a,i) (a)[(i)+0], (a)[(i)+1], (a)[(i)+2], \ (a)[(i)+3], (a)[(i)+4], (a)[(i)+5] /* * --------------------------------------------------------------------------- * emit a printf()-like debug message... but only if DEBUG_FLOAT was defined * --------------------------------------------------------------------------- */ #ifdef DEBUG_FLOAT #define dprintf(x) printf x #else #define dprintf(x) do { } while (0) #endif /* * --------------------------------------------------------------------------- * multiply * --------------------------------------------------------------------------- */ static int float_multiply(fp_limb *to, fp_limb *from) { fp_2limb temp[MANT_LIMBS * 2]; int i, j; /* * guaranteed that top bit of 'from' is set -- so we only have * to worry about _one_ bit shift to the left */ dprintf(("%s=" MANT_FMT "\n", "mul1", SOME_ARG(to, 0))); dprintf(("%s=" MANT_FMT "\n", "mul2", SOME_ARG(from, 0))); memset(temp, 0, sizeof temp); for (i = 0; i < MANT_LIMBS; i++) { for (j = 0; j < MANT_LIMBS; j++) { fp_2limb n; n = (fp_2limb) to[i] * (fp_2limb) from[j]; temp[i + j] += n >> LIMB_BITS; temp[i + j + 1] += (fp_limb)n; } } for (i = MANT_LIMBS * 2; --i;) { temp[i - 1] += temp[i] >> LIMB_BITS; temp[i] &= LIMB_MASK; } dprintf(("%s=" MANT_FMT "_" MANT_FMT "\n", "temp", SOME_ARG(temp, 0), SOME_ARG(temp, MANT_LIMBS))); if (temp[0] & LIMB_TOP_BIT) { for (i = 0; i < MANT_LIMBS; i++) { to[i] = temp[i] & LIMB_MASK; } dprintf(("%s=" MANT_FMT " (%i)\n", "prod", SOME_ARG(to, 0), 0)); return 0; } else { for (i = 0; i < MANT_LIMBS; i++) { to[i] = (temp[i] << 1) + !!(temp[i + 1] & LIMB_TOP_BIT); } dprintf(("%s=" MANT_FMT " (%i)\n", "prod", SOME_ARG(to, 0), -1)); return -1; } } /* * --------------------------------------------------------------------------- * read an exponent; returns INT32_MAX on error * --------------------------------------------------------------------------- */ static int32_t read_exponent(const char *string, int32_t max) { int32_t i = 0; bool neg = false; if (*string == '+') { string++; } else if (*string == '-') { neg = true; string++; } while (*string) { if (*string >= '0' && *string <= '9') { i = (i * 10) + (*string - '0'); /* * To ensure that underflows and overflows are * handled properly we must avoid wraparounds of * the signed integer value that is used to hold * the exponent. Therefore we cap the exponent at * +/-5000, which is slightly more/less than * what's required for normal and denormal numbers * in single, double, and extended precision, but * sufficient to avoid signed integer wraparound. */ if (i > max) i = max; } else if (*string == '_') { /* do nothing */ } else { nasm_nonfatal("invalid character in floating-point constant %s: '%c'", "exponent", *string); return INT32_MAX; } string++; } return neg ? -i : i; } /* * --------------------------------------------------------------------------- * convert * --------------------------------------------------------------------------- */ static bool ieee_flconvert(const char *string, fp_limb *mant, int32_t * exponent) { char digits[MANT_DIGITS]; char *p, *q, *r; fp_limb mult[MANT_LIMBS], bit; fp_limb *m; int32_t tenpwr, twopwr; int32_t extratwos; bool started, seendot, warned; warned = false; p = digits; tenpwr = 0; started = seendot = false; while (*string && *string != 'E' && *string != 'e') { if (*string == '.') { if (!seendot) { seendot = true; } else { nasm_nonfatal("too many periods in floating-point constant"); return false; } } else if (*string >= '0' && *string <= '9') { if (*string == '0' && !started) { if (seendot) { tenpwr--; } } else { started = true; if (p < digits + sizeof(digits)) { *p++ = *string - '0'; } else { if (!warned) { /*! *!float-toolong [on] too many digits in floating-point number *! warns about too many digits in floating-point numbers. */ nasm_warnf(WARN_FLOAT_TOOLONG|ERR_PASS2, "floating-point constant significand contains " "more than %i digits", MANT_DIGITS); warned = true; } } if (!seendot) { tenpwr++; } } } else if (*string == '_') { /* do nothing */ } else { nasm_nonfatalf(ERR_PASS2, "invalid character in floating-point constant %s: '%c'", "significand", *string); return false; } string++; } if (*string) { int32_t e; string++; /* eat the E */ e = read_exponent(string, 5000); if (e == INT32_MAX) return false; tenpwr += e; } /* * At this point, the memory interval [digits,p) contains a * series of decimal digits zzzzzzz, such that our number X * satisfies X = 0.zzzzzzz * 10^tenpwr. */ q = digits; dprintf(("X = 0.")); while (q < p) { dprintf(("%c", *q + '0')); q++; } dprintf((" * 10^%i\n", tenpwr)); /* * Now convert [digits,p) to our internal representation. */ bit = LIMB_TOP_BIT; for (m = mant; m < mant + MANT_LIMBS; m++) { *m = 0; } m = mant; q = digits; started = false; twopwr = 0; while (m < mant + MANT_LIMBS) { fp_limb carry = 0; while (p > q && !p[-1]) { p--; } if (p <= q) { break; } for (r = p; r-- > q;) { int32_t i; i = 2 * *r + carry; if (i >= 10) { carry = 1; i -= 10; } else { carry = 0; } *r = i; } if (carry) { *m |= bit; started = true; } if (started) { if (bit == 1) { bit = LIMB_TOP_BIT; m++; } else { bit >>= 1; } } else { twopwr--; } } twopwr += tenpwr; /* * At this point, the 'mant' array contains the first frac- * tional places of a base-2^16 real number which when mul- * tiplied by 2^twopwr and 5^tenpwr gives X. */ dprintf(("X = " MANT_FMT " * 2^%i * 5^%i\n", MANT_ARG, twopwr, tenpwr)); /* * Now multiply 'mant' by 5^tenpwr. */ if (tenpwr < 0) { /* mult = 5^-1 = 0.2 */ for (m = mult; m < mult + MANT_LIMBS - 1; m++) { *m = LIMB_BYTE(0xcc); } mult[MANT_LIMBS - 1] = LIMB_BYTE(0xcc)+1; extratwos = -2; tenpwr = -tenpwr; /* * If tenpwr was 1000...000b, then it becomes 1000...000b. See * the "ANSI C" comment below for more details on that case. * * Because we already truncated tenpwr to +5000...-5000 inside * the exponent parsing code, this shouldn't happen though. */ } else if (tenpwr > 0) { /* mult = 5^+1 = 5.0 */ mult[0] = (fp_limb)5 << (LIMB_BITS-3); /* 0xA000... */ for (m = mult + 1; m < mult + MANT_LIMBS; m++) { *m = 0; } extratwos = 3; } else { extratwos = 0; } while (tenpwr) { dprintf(("loop=" MANT_FMT " * 2^%i * 5^%i (%i)\n", MANT_ARG, twopwr, tenpwr, extratwos)); if (tenpwr & 1) { dprintf(("mant*mult\n")); twopwr += extratwos + float_multiply(mant, mult); } dprintf(("mult*mult\n")); extratwos = extratwos * 2 + float_multiply(mult, mult); tenpwr >>= 1; /* * In ANSI C, the result of right-shifting a signed integer is * considered implementation-specific. To ensure that the loop * terminates even if tenpwr was 1000...000b to begin with, we * manually clear the MSB, in case a 1 was shifted in. * * Because we already truncated tenpwr to +5000...-5000 inside * the exponent parsing code, this shouldn't matter; neverthe- * less it is the right thing to do here. */ tenpwr &= (uint32_t) - 1 >> 1; } /* * At this point, the 'mant' array contains the first frac- * tional places of a base-2^16 real number in [0.5,1) that * when multiplied by 2^twopwr gives X. Or it contains zero * of course. We are done. */ *exponent = twopwr; return true; } /* * --------------------------------------------------------------------------- * operations of specific bits * --------------------------------------------------------------------------- */ /* Set a bit, using *bigendian* bit numbering (0 = MSB) */ static void set_bit(fp_limb *mant, int bit) { mant[bit/LIMB_BITS] |= LIMB_TOP_BIT >> (bit & (LIMB_BITS-1)); } /* Test a single bit */ static int test_bit(const fp_limb *mant, int bit) { return (mant[bit/LIMB_BITS] >> (~bit & (LIMB_BITS-1))) & 1; } /* Report if the mantissa value is all zero */ static bool is_zero(const fp_limb *mant) { int i; for (i = 0; i < MANT_LIMBS; i++) if (mant[i]) return false; return true; } /* * --------------------------------------------------------------------------- * round a mantissa off after i words * --------------------------------------------------------------------------- */ #define ROUND_COLLECT_BITS \ do { \ m = mant[i] & (2*bit-1); \ for (j = i+1; j < MANT_LIMBS; j++) \ m = m | mant[j]; \ } while (0) #define ROUND_ABS_DOWN \ do { \ mant[i] &= ~(bit-1); \ for (j = i+1; j < MANT_LIMBS; j++) \ mant[j] = 0; \ return false; \ } while (0) #define ROUND_ABS_UP \ do { \ mant[i] = (mant[i] & ~(bit-1)) + bit; \ for (j = i+1; j < MANT_LIMBS; j++) \ mant[j] = 0; \ while (i > 0 && !mant[i]) \ ++mant[--i]; \ return !mant[0]; \ } while (0) static bool ieee_round(bool minus, fp_limb *mant, int bits) { fp_limb m = 0; int32_t j; int i = bits / LIMB_BITS; int p = bits % LIMB_BITS; fp_limb bit = LIMB_TOP_BIT >> p; if (rc == FLOAT_RC_NEAR) { if (mant[i] & bit) { mant[i] &= ~bit; ROUND_COLLECT_BITS; mant[i] |= bit; if (m) { ROUND_ABS_UP; } else { if (test_bit(mant, bits-1)) { ROUND_ABS_UP; } else { ROUND_ABS_DOWN; } } } else { ROUND_ABS_DOWN; } } else if (rc == FLOAT_RC_ZERO || rc == (minus ? FLOAT_RC_UP : FLOAT_RC_DOWN)) { ROUND_ABS_DOWN; } else { /* rc == (minus ? FLOAT_RC_DOWN : FLOAT_RC_UP) */ /* Round toward +/- infinity */ ROUND_COLLECT_BITS; if (m) { ROUND_ABS_UP; } else { ROUND_ABS_DOWN; } } return false; } /* Returns a value >= 16 if not a valid hex digit */ static unsigned int hexval(char c) { unsigned int v = (unsigned char) c; if (v >= '0' && v <= '9') return v - '0'; else return (v|0x20) - 'a' + 10; } /* Handle floating-point numbers with radix 2^bits and binary exponent */ static bool ieee_flconvert_bin(const char *string, int bits, fp_limb *mant, int32_t *exponent) { static const int log2tbl[16] = { -1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3 }; fp_limb mult[MANT_LIMBS + 1], *mp; int ms; int32_t twopwr; bool seendot, seendigit; unsigned char c; const int radix = 1 << bits; fp_limb v; twopwr = 0; seendot = seendigit = false; ms = 0; mp = NULL; memset(mult, 0, sizeof mult); while ((c = *string++) != '\0') { if (c == '.') { if (!seendot) seendot = true; else { nasm_nonfatal("too many periods in floating-point constant"); return false; } } else if ((v = hexval(c)) < (unsigned int)radix) { if (!seendigit && v) { int l = log2tbl[v]; seendigit = true; mp = mult; ms = (LIMB_BITS-1)-l; twopwr += l+1-bits; } if (seendigit) { if (ms < 0) { /* Cast to fp_2limb as ms == -LIMB_BITS is possible. */ *mp |= (fp_2limb)v >> -ms; mp++; if (mp > &mult[MANT_LIMBS]) mp = &mult[MANT_LIMBS]; /* Guard slot */ ms += LIMB_BITS; } *mp |= v << ms; ms -= bits; if (!seendot) twopwr += bits; } else { if (seendot) twopwr -= bits; } } else if (c == 'p' || c == 'P') { int32_t e; e = read_exponent(string, 20000); if (e == INT32_MAX) return false; twopwr += e; break; } else if (c == '_') { /* ignore */ } else { nasm_nonfatal("floating-point constant: `%c' is invalid character", c); return false; } } if (!seendigit) { memset(mant, 0, MANT_LIMBS*sizeof(fp_limb)); /* Zero */ *exponent = 0; } else { memcpy(mant, mult, MANT_LIMBS*sizeof(fp_limb)); *exponent = twopwr; } return true; } /* * Shift a mantissa to the right by i bits. */ static void ieee_shr(fp_limb *mant, int i) { fp_limb n, m; int j = 0; int sr, sl, offs; sr = i % LIMB_BITS; sl = LIMB_BITS-sr; offs = i/LIMB_BITS; if (sr == 0) { if (offs) for (j = MANT_LIMBS-1; j >= offs; j--) mant[j] = mant[j-offs]; } else if (MANT_LIMBS-1-offs < 0) { j = MANT_LIMBS-1; } else { n = mant[MANT_LIMBS-1-offs] >> sr; for (j = MANT_LIMBS-1; j > offs; j--) { m = mant[j-offs-1]; mant[j] = (m << sl) | n; n = m >> sr; } mant[j--] = n; } while (j >= 0) mant[j--] = 0; } /* Produce standard IEEE formats, with implicit or explicit integer bit; this makes the following assumptions: - the sign bit is the MSB, followed by the exponent, followed by the integer bit if present. - the sign bit plus exponent fit in 16 bits. - the exponent bias is 2^(n-1)-1 for an n-bit exponent */ struct ieee_format { int bytes; int mantissa; /* Fractional bits in the mantissa */ int explicit; /* Explicit integer */ int exponent; /* Bits in the exponent */ }; /* * The 16- and 128-bit formats are expected to be in IEEE 754r. * AMD SSE5 uses the 16-bit format. * * The 32- and 64-bit formats are the original IEEE 754 formats. * * The 80-bit format is x87-specific, but widely used. * * The 8-bit format appears to be the consensus 8-bit floating-point * format. It is apparently used in graphics applications. */ static const struct ieee_format ieee_8 = { 1, 3, 0, 4 }; static const struct ieee_format ieee_16 = { 2, 10, 0, 5 }; static const struct ieee_format ieee_32 = { 4, 23, 0, 8 }; static const struct ieee_format ieee_64 = { 8, 52, 0, 11 }; static const struct ieee_format ieee_80 = { 10, 63, 1, 15 }; static const struct ieee_format ieee_128 = { 16, 112, 0, 15 }; /* Types of values we can generate */ enum floats { FL_ZERO, FL_DENORMAL, FL_NORMAL, FL_INFINITY, FL_QNAN, FL_SNAN }; static int to_packed_bcd(const char *str, const char *p, int s, uint8_t *result, const struct ieee_format *fmt) { int n = 0; char c; int tv = -1; if (fmt != &ieee_80) { nasm_nonfatal("packed BCD requires an 80-bit format"); return 0; } while (p >= str) { c = *p--; if (c >= '0' && c <= '9') { if (tv < 0) { if (n == 9) nasm_warnf(ERR_PASS2, "packed BCD truncated to 18 digits"); tv = c-'0'; } else { if (n < 9) *result++ = tv + ((c-'0') << 4); n++; tv = -1; } } else if (c == '_') { /* do nothing */ } else { nasm_nonfatal("invalid character `%c' in packed BCD constant", c); return 0; } } if (tv >= 0) { if (n < 9) *result++ = tv; n++; } while (n < 9) { *result++ = 0; n++; } *result = (s < 0) ? 0x80 : 0; return 1; /* success */ } static int to_float(const char *str, int s, uint8_t *result, const struct ieee_format *fmt) { fp_limb mant[MANT_LIMBS]; int32_t exponent = 0; const int32_t expmax = 1 << (fmt->exponent - 1); fp_limb one_mask = LIMB_TOP_BIT >> ((fmt->exponent+fmt->explicit) % LIMB_BITS); const int one_pos = (fmt->exponent+fmt->explicit)/LIMB_BITS; int i; int shift; enum floats type; bool ok; const bool minus = s < 0; const int bits = fmt->bytes * 8; const char *strend; nasm_assert(str[0]); strend = strchr(str, '\0'); if (strend[-1] == 'P' || strend[-1] == 'p') return to_packed_bcd(str, strend-2, s, result, fmt); if (str[0] == '_') { /* Special tokens */ switch (str[2]) { case 'n': /* __nan__ */ case 'N': case 'q': /* __qnan__ */ case 'Q': type = FL_QNAN; break; case 's': /* __snan__ */ case 'S': type = FL_SNAN; break; case 'i': /* __infinity__ */ case 'I': type = FL_INFINITY; break; default: nasm_nonfatal("internal error: unknown FP constant token `%s'", str); type = FL_QNAN; break; } } else { if (str[0] == '0') { switch (str[1]) { case 'x': case 'X': case 'h': case 'H': ok = ieee_flconvert_bin(str+2, 4, mant, &exponent); break; case 'o': case 'O': case 'q': case 'Q': ok = ieee_flconvert_bin(str+2, 3, mant, &exponent); break; case 'b': case 'B': case 'y': case 'Y': ok = ieee_flconvert_bin(str+2, 1, mant, &exponent); break; case 'd': case 'D': case 't': case 'T': ok = ieee_flconvert(str+2, mant, &exponent); break; case 'p': case 'P': return to_packed_bcd(str+2, strend-1, s, result, fmt); default: /* Leading zero was just a zero? */ ok = ieee_flconvert(str, mant, &exponent); break; } } else if (str[0] == '$') { ok = ieee_flconvert_bin(str+1, 4, mant, &exponent); } else { ok = ieee_flconvert(str, mant, &exponent); } if (!ok) { type = FL_QNAN; } else if (mant[0] & LIMB_TOP_BIT) { /* * Non-zero. */ exponent--; if (exponent >= 2 - expmax && exponent <= expmax) { type = FL_NORMAL; } else if (exponent > 0) { nasm_warnf(WARN_FLOAT_OVERFLOW|ERR_PASS2, "overflow in floating-point constant"); type = FL_INFINITY; } else { /* underflow or denormal; the denormal code handles actual underflow. */ type = FL_DENORMAL; } } else { /* Zero */ type = FL_ZERO; } } switch (type) { case FL_ZERO: zero: memset(mant, 0, sizeof mant); break; case FL_DENORMAL: { shift = -(exponent + expmax - 2 - fmt->exponent) + fmt->explicit; ieee_shr(mant, shift); ieee_round(minus, mant, bits); if (mant[one_pos] & one_mask) { /* One's position is set, we rounded up into normal range */ exponent = 1; if (!fmt->explicit) mant[one_pos] &= ~one_mask; /* remove explicit one */ mant[0] |= exponent << (LIMB_BITS-1 - fmt->exponent); } else { if (daz || is_zero(mant)) { /*! *!float-underflow [off] floating point underflow *! warns about floating point underflow (a nonzero *! constant rounded to zero.) */ nasm_warnf(WARN_FLOAT_UNDERFLOW|ERR_PASS2, "underflow in floating-point constant"); goto zero; } else { /*! *!float-denorm [off] floating point denormal *! warns about denormal floating point constants. */ nasm_warnf(WARN_FLOAT_DENORM|ERR_PASS2, "denormal floating-point constant"); } } break; } case FL_NORMAL: exponent += expmax - 1; ieee_shr(mant, fmt->exponent+fmt->explicit); ieee_round(minus, mant, bits); /* did we scale up by one? */ if (test_bit(mant, fmt->exponent+fmt->explicit-1)) { ieee_shr(mant, 1); exponent++; if (exponent >= (expmax << 1)-1) { /*! *!float-overflow [on] floating point overflow *! warns about floating point underflow. */ nasm_warnf(WARN_FLOAT_OVERFLOW|ERR_PASS2, "overflow in floating-point constant"); type = FL_INFINITY; goto overflow; } } if (!fmt->explicit) mant[one_pos] &= ~one_mask; /* remove explicit one */ mant[0] |= exponent << (LIMB_BITS-1 - fmt->exponent); break; case FL_INFINITY: case FL_QNAN: case FL_SNAN: overflow: memset(mant, 0, sizeof mant); mant[0] = (((fp_limb)1 << fmt->exponent)-1) << (LIMB_BITS-1 - fmt->exponent); if (fmt->explicit) mant[one_pos] |= one_mask; if (type == FL_QNAN) set_bit(mant, fmt->exponent+fmt->explicit+1); else if (type == FL_SNAN) set_bit(mant, fmt->exponent+fmt->explicit+fmt->mantissa); break; } mant[0] |= minus ? LIMB_TOP_BIT : 0; for (i = fmt->bytes - 1; i >= 0; i--) *result++ = mant[i/LIMB_BYTES] >> (((LIMB_BYTES-1)-(i%LIMB_BYTES))*8); return 1; /* success */ } int float_const(const char *number, int sign, uint8_t *result, int bytes) { switch (bytes) { case 1: return to_float(number, sign, result, &ieee_8); case 2: return to_float(number, sign, result, &ieee_16); case 4: return to_float(number, sign, result, &ieee_32); case 8: return to_float(number, sign, result, &ieee_64); case 10: return to_float(number, sign, result, &ieee_80); case 16: return to_float(number, sign, result, &ieee_128); default: nasm_panic("strange value %d passed to float_const", bytes); return 0; } } /* Set floating-point options */ int float_option(const char *option) { if (!nasm_stricmp(option, "daz")) { daz = true; return 0; } else if (!nasm_stricmp(option, "nodaz")) { daz = false; return 0; } else if (!nasm_stricmp(option, "near")) { rc = FLOAT_RC_NEAR; return 0; } else if (!nasm_stricmp(option, "down")) { rc = FLOAT_RC_DOWN; return 0; } else if (!nasm_stricmp(option, "up")) { rc = FLOAT_RC_UP; return 0; } else if (!nasm_stricmp(option, "zero")) { rc = FLOAT_RC_ZERO; return 0; } else if (!nasm_stricmp(option, "default")) { rc = FLOAT_RC_NEAR; daz = false; return 0; } else { return -1; /* Unknown option */ } }