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Fix error handling and a percision issue in float core (#6469)

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* fix error handling and percision issues in float core
* fix rz_float_cast_float on zero input and add tests
This commit is contained in:
مصطفي محمود كمال الدين 2026-06-14 17:48:44 +03:00 committed by GitHub
parent f91ef729bf
commit afd6607fe2
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GPG key ID: B5690EEEBB952194
3 changed files with 79 additions and 5 deletions
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4
librz/il/theory_fbasic.c
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@ -357,6 +357,10 @@ void *rz_il_handler_fexcept(RzILVM *vm, RzILOpPure *op, RzILTypePure *type) {
e = n->exception & RZ_FLOAT_E_INEXACT;
rz_il_vm_event_add(vm, rz_il_event_exception_new(RZ_IL_EVENT_EXC_FP_INEXACT));
break;
case RZ_FLOAT_E_INVALID_OP:
e = n->exception & RZ_FLOAT_E_INVALID_OP;
rz_il_vm_event_add(vm, rz_il_event_exception_new(RZ_IL_EVENT_EXC_FP_INVALID_OP));
break;
default:;
}

13
librz/util/float/float.c
View file

@ -1501,6 +1501,10 @@ RZ_API RZ_OWN RzFloat *rz_float_cast_float(RZ_NONNULL RzBitVector *bv, RzFloatFo
ut32 exp_max_no_bias = bias;
ut32 width = rz_bv_len(bv) - rz_bv_clz(bv);
// Zero has no highest set bit; handle it before width - 1 underflows.
if (width == 0) {
return rz_float_new_zero(format, false);
}
ut32 order = width - 1;
if (order > exp_max_no_bias) {
// error: not representable
@ -1584,8 +1588,9 @@ RZ_API RZ_OWN RzBitVector *rz_float_cast_sint(RZ_NONNULL RzFloat *f, ut32 length
RzBitVector *sig = rz_float_get_mantissa(f);
bool is_zero = rz_bv_is_zero_vector(sig) && exp == 0;
// sub normal one has no hidden bit, others should set to 1
if (!is_subnormal) {
// binary80 stores the integer bit explicitly in the mantissa; all other
// normal formats use a hidden bit that must be injected here
if (!is_subnormal && format != RZ_FLOAT_IEEE754_BIN_80) {
rz_bv_set(sig, man_len, true);
}
@ -1639,9 +1644,7 @@ RZ_API RZ_OWN RzBitVector *rz_float_cast_sint(RZ_NONNULL RzFloat *f, ut32 length
tmp = NULL;
}
// WARN: possible overflow if length < exp_no_bias
// WARN: higher bits may be cut off
rz_bv_copy_nbits(ret, 0, rounded, 0, rz_bv_len(rounded));
rz_bv_copy_nbits(ret, 0, rounded, 0, RZ_MIN(rz_bv_len(rounded), length));
rz_bv_free(rounded);
return ret;
}

67
test/unit/test_float.c
View file

@ -1394,6 +1394,19 @@ bool f32_ieee_cast_test(void) {
rz_float_free(expect);
rz_bv_free(val);
// 1-1b. zero
val = rz_bv_new_zero(32);
expect = rz_float_new_zero(RZ_FLOAT_IEEE754_BIN_32, false);
cast_val = rz_float_cast_float(val, RZ_FLOAT_IEEE754_BIN_32, RZ_FLOAT_RMODE_RNE);
mu_assert_false(rz_float_cmp(expect, cast_val), "test (cast-float 0)");
rz_float_free(cast_val);
cast_val = rz_float_cast_sfloat(val, RZ_FLOAT_IEEE754_BIN_32, RZ_FLOAT_RMODE_RNE);
mu_assert_false(rz_float_cmp(expect, cast_val), "test (cast-sfloat 0)");
rz_float_free(cast_val);
rz_float_free(expect);
rz_bv_free(val);
// 1-2. normal
val = rz_bv_new_from_ut64(32, 12345678);
expect = rz_float_new_from_f32(12345678.0f);
@ -1566,6 +1579,58 @@ static RzFloat *new_f80_from_bytes(const char *bytes) {
return ret;
}
bool f80_ieee_cast_sint_test(void) {
// binary80 has no hidden bit: the integer part of the significand is stored
// explicitly, unlike other IEEE-754 formats where it is implicit for normals
RzFloat *f80_val = new_f80_from_bytes("\x40\x00\xc0\x00\x00\x00\x00\x00\x00\x00");
RzBitVector *expected_bv = rz_bv_new_from_ut64(32, 3);
RzBitVector *cast_bv = rz_float_cast_sint(f80_val, 32, RZ_FLOAT_RMODE_RNE);
mu_assert_true(rz_bv_eq(expected_bv, cast_bv), "cast-sint preserves 3.0 in ieee754-bin80");
rz_float_free(f80_val);
rz_bv_free(expected_bv);
rz_bv_free(cast_bv);
mu_end;
}
bool f80_ieee_cast_sint_large_test(void) {
RzFloat *f80_val = new_f80_from_bytes("\x40\x1b\x80\x00\x00\x00\x00\x00\x00\x00");
RzBitVector *expected_bv = rz_bv_new_from_ut64(32, 1ULL << 28);
RzBitVector *cast_bv = rz_float_cast_sint(f80_val, 32, RZ_FLOAT_RMODE_RNE);
mu_assert_true(rz_bv_eq(expected_bv, cast_bv), "cast-sint preserves 2^28 in ieee754-bin80");
rz_float_free(f80_val);
rz_bv_free(expected_bv);
rz_bv_free(cast_bv);
f80_val = new_f80_from_bytes("\x40\x1c\x80\x00\x00\x00\x00\x00\x00\x00");
expected_bv = rz_bv_new_from_ut64(32, 1ULL << 29);
cast_bv = rz_float_cast_sint(f80_val, 32, RZ_FLOAT_RMODE_RNE);
mu_assert_true(rz_bv_eq(expected_bv, cast_bv), "cast-sint preserves 2^29 in ieee754-bin80");
rz_float_free(f80_val);
rz_bv_free(expected_bv);
rz_bv_free(cast_bv);
f80_val = new_f80_from_bytes("\x40\x1d\x80\x00\x00\x00\x00\x00\x00\x00");
expected_bv = rz_bv_new_from_ut64(32, 1ULL << 30);
cast_bv = rz_float_cast_sint(f80_val, 32, RZ_FLOAT_RMODE_RNE);
mu_assert_true(rz_bv_eq(expected_bv, cast_bv), "cast-sint preserves 2^30 in ieee754-bin80");
rz_float_free(f80_val);
rz_bv_free(expected_bv);
rz_bv_free(cast_bv);
f80_val = new_f80_from_bytes("\x40\x1e\x80\x00\x00\x00\x00\x00\x00\x00");
expected_bv = rz_bv_new_from_ut64(32, 1ULL << 31);
cast_bv = rz_float_cast_sint(f80_val, 32, RZ_FLOAT_RMODE_RNE);
mu_assert_true(rz_bv_eq(expected_bv, cast_bv), "cast-sint preserves 2^31 in ieee754-bin80");
rz_float_free(f80_val);
rz_bv_free(expected_bv);
rz_bv_free(cast_bv);
mu_end;
}
bool f80_ieee_add_test(void) {
RzFloat *x_f80 = new_f80_from_bytes("\x40\x00\xa6\x5f\x8f\x48\x12\x44\xca\x0b");
RzFloat *y_f80 = new_f80_from_bytes("\x3f\xfd\xc4\xf4\x67\x6e\x7d\x93\x40\x00");
@ -1709,6 +1774,8 @@ bool all_tests() {
mu_run_test(f32_new_round_test);
mu_run_test(f32_ieee_fround_test);
mu_run_test(f32_ieee_cast_test);
mu_run_test(f80_ieee_cast_sint_test);
mu_run_test(f80_ieee_cast_sint_large_test);
mu_run_test(f80_ieee_add_test);
mu_run_test(f80_ieee_sub_test);
mu_run_test(f80_ieee_mul_test);