static int value_size;
static int max_precision;
+/** Exact flag. */
+static int fc_exact = 1;
+
#if 0
static void fail_char(const char *str, unsigned int len, int pos) {
if (*(str+pos))
return packed;
}
-static void normalize(const fp_value *in_val, fp_value *out_val, int sticky) {
+/**
+ * Normalize a fp_value.
+ *
+ * @return non-zero if result is exact
+ */
+static int normalize(const fp_value *in_val, fp_value *out_val, int sticky) {
+ int exact = 1;
int hsb;
char lsb, guard, round, round_dir = 0;
char *temp = alloca(value_size);
out_val->desc.clss = NORMAL;
- /* mantissa all zeros, so zero exponent (because of explicit one)*/
+ /* mantissa all zeros, so zero exponent (because of explicit one) */
if (hsb == 2 + in_val->desc.mantissa_size) {
sc_val_from_ulong(0, _exp(out_val));
hsb = -1;
_shift_right(_mant(in_val), temp, _mant(out_val));
/* remember if some bits were shifted away */
- if (!sticky) sticky = sc_had_carry();
-
+ if (sc_had_carry()) {
+ exact = 0;
+ sticky = 1;
+ }
sc_add(_exp(in_val), temp, _exp(out_val));
} else if (hsb > -1) {
/* shift left */
sc_sub(temp, _exp(out_val), NULL);
_shift_right(_mant(out_val), sc_get_buffer(), _mant(out_val));
- if (!sticky) sticky = sc_had_carry();
+ if (sc_had_carry()) {
+ exact = 0;
+ sticky = 1;
+ }
/* denormalized means exponent of zero */
sc_val_from_ulong(0, _exp(out_val));
if (lsb != 0) {
sc_val_from_long(lsb, temp);
sc_add(_mant(out_val), temp, _mant(out_val));
+ exact = 0;
}
/* could have rounded down to zero */
if ((out_val->desc.clss != SUBNORMAL) && (hsb < -1)) {
sc_val_from_ulong(1, temp);
_shift_right(_mant(out_val), temp, _mant(out_val));
-
+ if (exact && sc_had_carry())
+ exact = 0;
sc_add(_exp(out_val), temp, _exp(out_val));
} else if ((out_val->desc.clss == SUBNORMAL) && (hsb == -1)) {
/* overflow caused the mantissa to be normal again,
}
}
}
+ return exact;
}
/**
char sign, res_sign;
char sticky;
+ fc_exact = 1;
+
handle_NAN(a, b, result);
/* make sure result has a descriptor */
_shift_right(_mant(b), exp_diff, temp);
sticky = sc_had_carry();
+ fc_exact &= !sticky;
if (sticky && sign) {
/* if subtracting a little more than the represented value or adding a little
/* resulting exponent is the bigger one */
memmove(_exp(result), _exp(a), value_size);
- normalize(result, result, sticky);
+ fc_exact &= normalize(result, result, sticky);
}
/**
* calculate a * b
*/
static void _fmul(const fp_value *a, const fp_value *b, fp_value *result) {
+ int sticky;
char *temp;
char res_sign;
+ fc_exact = 1;
+
handle_NAN(a, b, result);
temp = alloca(value_size);
sc_val_from_ulong(2 + result->desc.mantissa_size, temp);
_shift_right(_mant(result), temp, _mant(result));
+ sticky = sc_had_carry();
+ fc_exact &= !sticky;
- normalize(result, result, sc_had_carry());
+ fc_exact &= normalize(result, result, sticky);
}
/**
* calculate a / b
*/
static void _fdiv(const fp_value *a, const fp_value *b, fp_value *result) {
+ int sticky;
char *temp, *dividend;
char res_sign;
+ fc_exact = 1;
+
handle_NAN(a, b, result);
temp = alloca(value_size);
sc_val_from_ulong(1, divisor);
_shift_right(_mant(b), divisor, divisor);
sc_div(dividend, divisor, _mant(result));
+ sticky = sc_had_carry();
+ fc_exact &= !sticky;
}
- normalize(result, result, sc_had_carry());
+ fc_exact &= normalize(result, result, sticky);
}
#if 0
int exp_bias, exp_val;
char *temp;
+ /* fixme: can be exact */
+ fc_exact = 0;
+
temp = alloca(value_size);
if (a != result)
if (result == NULL) result = calc_buffer;
temp = alloca(value_size);
+ /* CLEAR the buffer */
+ memset(result, 0, fc_get_buffer_length());
+
result->desc.exponent_size = exp_size;
result->desc.mantissa_size = mant_size;
return result;
}
+ if (value->desc.clss == NAN) {
+ if (sc_get_highest_set_bit(_mant(value)) == value->desc.mantissa_size + 1)
+ return fc_get_qnan(exp_size, mant_size, result);
+ else
+ return fc_get_snan(exp_size, mant_size, result);
+ }
+
/* set the descriptor of the new value */
result->desc.exponent_size = exp_size;
result->desc.mantissa_size = mant_size;
free(calc_buffer); calc_buffer = NULL;
}
+#ifdef FLTCALC_TRACE_CALC
static char buffer[100];
+#endif
/* definition of interface functions */
fp_value *fc_add(const fp_value *a, const fp_value *b, fp_value *result) {
fp_value *fc_rnd(const fp_value *a, fp_value *result) {
if (result == NULL) result = calc_buffer;
+ (void) a;
TRACEPRINTF(("%s ", fc_print(a, buffer, sizeof(buffer), FC_PACKED)));
TRACEPRINTF(("rounded to integer "));
return result;
}
+/*
+ * convert a floating point value into an sc value ...
+ */
+int fc_flt2int(const fp_value *a, void *result, ir_mode *dst_mode) {
+ if (a->desc.clss == NORMAL) {
+ int exp_bias = (1 << (a->desc.exponent_size - 1)) - 1;
+ int exp_val = sc_val_to_long(_exp(a)) - exp_bias;
+ int shift, highest;
+
+ if (a->sign && !mode_is_signed(dst_mode)) {
+ /* FIXME: for now we cannot convert this */
+ return 0;
+ }
+
+ assert(exp_val >= 0 && "floating point value not integral before fc_flt2int() call");
+ shift = exp_val - a->desc.mantissa_size - 2;
+
+ if (shift > 0) {
+ sc_shlI(_mant(a), shift, 64, 0, result);
+ } else {
+ sc_shrI(_mant(a), -shift, 64, 0, result);
+ }
+
+ /* check for overflow */
+ highest = sc_get_highest_set_bit(result);
+
+ if (mode_is_signed(dst_mode)) {
+ if (highest == sc_get_lowest_set_bit(result)) {
+ /* need extra test for MIN_INT */
+ if (highest >= get_mode_size_bits(dst_mode)) {
+ /* FIXME: handle overflow */
+ return 0;
+ }
+ } else {
+ if (highest >= get_mode_size_bits(dst_mode) - 1) {
+ /* FIXME: handle overflow */
+ return 0;
+ }
+ }
+ } else {
+ if (highest >= get_mode_size_bits(dst_mode)) {
+ /* FIXME: handle overflow */
+ return 0;
+ }
+ }
+
+ if (a->sign)
+ sc_neg(result, result);
+
+ return 1;
+ }
+ else if (a->desc.clss == ZERO) {
+ sc_zero(result);
+ return 1;
+ }
+ return 0;
+}
+
+
unsigned fc_set_immediate_precision(unsigned bits) {
unsigned old = immediate_prec;
immediate_prec = bits;
return old;
}
+
+int fc_is_exact(void) {
+ return fc_exact;
+}
projects / libfirm / blobdiff