| author |  Andrew Kelley <andrew@ziglang.org> 2019-03-21 16:17:29-04:00 |
| committer | Andrew Kelley <andrew@ziglang.org> 2019-03-21 16:17:29-04:00 |
| log | af509c68b01c8645e5efaeec7ea11e809f34ba7d |
| tree | dad7a1a927522c19f547a910d68647e0ce989a57 |
| parent | b5cc92f16391b1ff5d75e5e6b072b8338b3e8218 |
| signature |  Commit is signed but in an unrecognized format. |
fix parsing of large hex float literals
closes #20832 files changed, 82 insertions(+), 10 deletions(-)
test- stage1
- behavior
src/tokenizer.cpp+18-10
| ... | ... | @@ -326,7 +326,7 @@ static void end_float_token(Tokenize *t) { |
| 326 | 326 | return; |
| 327 | 327 | } |
| 328 | 328 | |
| 329 | // A SoftFloat-3d float128 is represented internally as a standard | |
| 329 | // A SoftFloat-3e float128 is represented internally as a standard | |
| 330 | 330 | // quad-precision float with 15bit exponent and 113bit fractional. |
| 331 | 331 | union { uint64_t repr[2]; float128_t actual; } f_bits; |
| 332 | 332 | |
| ... | ... | @@ -345,29 +345,37 @@ static void end_float_token(Tokenize *t) { |
| 345 | 345 | return; |
| 346 | 346 | } |
| 347 | 347 | |
| 348 | uint64_t sig_bits[2] = {0, 0}; | |
| 349 | bigint_write_twos_complement(&t->significand, (uint8_t*) sig_bits, 128, false); | |
| 350 | ||
| 351 | const uint64_t shift = 112 - significand_magnitude_in_bin; | |
| 352 | const uint64_t exp_shift = 48; | |
| 353 | // Mask the sign bit to 0 since always non-negative lex | |
| 354 | const uint64_t exp_mask = 0xffffull << exp_shift; | |
| 348 | const int shift = 112 - significand_magnitude_in_bin; | |
| 355 | 349 | |
| 356 | 350 | // must be special-cased to avoid undefined behavior on shift == 64 |
| 357 | 351 | if (shift == 128) { |
| 352 | uint64_t sig_bits[2] = {0, 0}; | |
| 353 | bigint_write_twos_complement(&t->significand, (uint8_t*) sig_bits, 128, false); | |
| 358 | 354 | f_bits.repr[0] = 0; |
| 359 | 355 | f_bits.repr[1] = sig_bits[0]; |
| 360 | 356 | } else if (shift == 0) { |
| 361 | f_bits.repr[0] = sig_bits[0]; | |
| 362 | f_bits.repr[1] = sig_bits[1]; | |
| 357 | bigint_write_twos_complement(&t->significand, (uint8_t*) f_bits.repr, 128, false); | |
| 363 | 358 | } else if (shift >= 64) { |
| 359 | uint64_t sig_bits[2] = {0, 0}; | |
| 360 | bigint_write_twos_complement(&t->significand, (uint8_t*) sig_bits, 128, false); | |
| 364 | 361 | f_bits.repr[0] = 0; |
| 365 | 362 | f_bits.repr[1] = sig_bits[0] << (shift - 64); |
| 363 | } else if (shift < 0) { | |
| 364 | BigInt shift_bigint; | |
| 365 | bigint_init_unsigned(&shift_bigint, -shift); | |
| 366 | BigInt shifted_significand; | |
| 367 | bigint_shr(&shifted_significand, &t->significand, &shift_bigint); | |
| 368 | bigint_write_twos_complement(&shifted_significand, (uint8_t*) f_bits.repr, 128, false); | |
| 366 | 369 | } else { |
| 370 | uint64_t sig_bits[2] = {0, 0}; | |
| 371 | bigint_write_twos_complement(&t->significand, (uint8_t*) sig_bits, 128, false); | |
| 367 | 372 | f_bits.repr[0] = sig_bits[0] << shift; |
| 368 | 373 | f_bits.repr[1] = (sig_bits[1] << shift) | (sig_bits[0] >> (64 - shift)); |
| 369 | 374 | } |
| 370 | 375 | |
| 376 | const uint64_t exp_shift = 48; | |
| 377 | // Mask the sign bit to 0 since always non-negative lex | |
| 378 | const uint64_t exp_mask = 0xffffull << exp_shift; | |
| 371 | 379 | f_bits.repr[1] &= ~exp_mask; |
| 372 | 380 | f_bits.repr[1] |= (uint64_t)(t->exponent_in_bin_or_dec + 16383) << exp_shift; |
| 373 | 381 | } |
test/stage1/behavior/math.zig+64
| ... | ... | @@ -307,6 +307,70 @@ test "quad hex float literal parsing accurate" { |
| 307 | 307 | // implied 1 is dropped, with an exponent of 0 (0x3fff) after biasing. |
| 308 | 308 | const expected: u128 = 0x3fff1111222233334444555566667777; |
| 309 | 309 | expect(@bitCast(u128, a) == expected); |
| 310 | ||
| 311 | const S = struct { | |
| 312 | fn doTheTest() void { | |
| 313 | var f1: f128 = 0x1.2eab345678439abcdefea56782346p+5; | |
| 314 | expect(@bitCast(u128, f1) == 0x40042eab345678439abcdefea5678234); | |
| 315 | const exp2ft = []f64{ | |
| 316 | 0x1.6a09e667f3bcdp-1, | |
| 317 | 0x1.7a11473eb0187p-1, | |
| 318 | 0x1.8ace5422aa0dbp-1, | |
| 319 | 0x1.9c49182a3f090p-1, | |
| 320 | 0x1.ae89f995ad3adp-1, | |
| 321 | 0x1.c199bdd85529cp-1, | |
| 322 | 0x1.d5818dcfba487p-1, | |
| 323 | 0x1.ea4afa2a490dap-1, | |
| 324 | 0x1.0000000000000p+0, | |
| 325 | 0x1.0b5586cf9890fp+0, | |
| 326 | 0x1.172b83c7d517bp+0, | |
| 327 | 0x1.2387a6e756238p+0, | |
| 328 | 0x1.306fe0a31b715p+0, | |
| 329 | 0x1.3dea64c123422p+0, | |
| 330 | 0x1.4bfdad5362a27p+0, | |
| 331 | 0x1.5ab07dd485429p+0, | |
| 332 | 0x1.8p23, | |
| 333 | 0x1.62e430p-1, | |
| 334 | 0x1.ebfbe0p-3, | |
| 335 | 0x1.c6b348p-5, | |
| 336 | 0x1.3b2c9cp-7, | |
| 337 | 0x1.0p127, | |
| 338 | -0x1.0p-149, | |
| 339 | }; | |
| 340 | ||
| 341 | const answers = []u64{ | |
| 342 | 0x3fe6a09e667f3bcd, | |
| 343 | 0x3fe7a11473eb0187, | |
| 344 | 0x3fe8ace5422aa0db, | |
| 345 | 0x3fe9c49182a3f090, | |
| 346 | 0x3feae89f995ad3ad, | |
| 347 | 0x3fec199bdd85529c, | |
| 348 | 0x3fed5818dcfba487, | |
| 349 | 0x3feea4afa2a490da, | |
| 350 | 0x3ff0000000000000, | |
| 351 | 0x3ff0b5586cf9890f, | |
| 352 | 0x3ff172b83c7d517b, | |
| 353 | 0x3ff2387a6e756238, | |
| 354 | 0x3ff306fe0a31b715, | |
| 355 | 0x3ff3dea64c123422, | |
| 356 | 0x3ff4bfdad5362a27, | |
| 357 | 0x3ff5ab07dd485429, | |
| 358 | 0x4168000000000000, | |
| 359 | 0x3fe62e4300000000, | |
| 360 | 0x3fcebfbe00000000, | |
| 361 | 0x3fac6b3480000000, | |
| 362 | 0x3f83b2c9c0000000, | |
| 363 | 0x47e0000000000000, | |
| 364 | 0xb6a0000000000000, | |
| 365 | }; | |
| 366 | ||
| 367 | for (exp2ft) |x, i| { | |
| 368 | expect(@bitCast(u64, x) == answers[i]); | |
| 369 | } | |
| 370 | } | |
| 371 | }; | |
| 372 | S.doTheTest(); | |
| 373 | comptime S.doTheTest(); | |
| 310 | 374 | } |
| 311 | 375 | |
| 312 | 376 | test "hex float literal within range" { |