@@ -83,7 +83,6 @@ this code that are retained.
* target-dependent and needs the TARGET_* macros.
*/
#include "qemu/osdep.h"
-
#include "fpu/softfloat.h"
/* We only need stdlib for abort() */
@@ -186,6 +185,91 @@ static inline flag extractFloat64Sign(float64 a)
return float64_val(a) >> 63;
}
+/*
+ * Classify a floating point number. Everything above float_class_qnan
+ * is a NaN so cls >= float_class_qnan is any NaN.
+ */
+
+typedef enum __attribute__ ((__packed__)) {
+ float_class_unclassified,
+ float_class_zero,
+ float_class_normal,
+ float_class_inf,
+ float_class_qnan, /* all NaNs from here */
+ float_class_snan,
+ float_class_dnan,
+ float_class_msnan, /* maybe silenced */
+} FloatClass;
+
+/*
+ * Structure holding all of the decomposed parts of a float. The
+ * exponent is unbiased and the fraction is normalized. All
+ * calculations are done with a 64 bit fraction and then rounded as
+ * appropriate for the final format.
+ *
+ * Thanks to the packed FloatClass a decent compiler should be able to
+ * fit the whole structure into registers and avoid using the stack
+ * for parameter passing.
+ */
+
+typedef struct {
+ uint64_t frac;
+ int32_t exp;
+ FloatClass cls;
+ bool sign;
+} FloatParts;
+
+#define DECOMPOSED_BINARY_POINT (64 - 2)
+#define DECOMPOSED_IMPLICIT_BIT (1ull << DECOMPOSED_BINARY_POINT)
+#define DECOMPOSED_OVERFLOW_BIT (DECOMPOSED_IMPLICIT_BIT << 1)
+
+/* Structure holding all of the relevant parameters for a format.
+ * exp_size: the size of the exponent field
+ * exp_bias: the offset applied to the exponent field
+ * exp_max: the maximum normalised exponent
+ * frac_size: the size of the fraction field
+ * frac_shift: shift to normalise the fraction with DECOMPOSED_BINARY_POINT
+ * The following are computed based the size of fraction
+ * frac_lsb: least significant bit of fraction
+ * fram_lsbm1: the bit bellow the least significant bit (for rounding)
+ * round_mask/roundeven_mask: masks used for rounding
+ */
+typedef struct {
+ int exp_size;
+ int exp_bias;
+ int exp_max;
+ int frac_size;
+ int frac_shift;
+ uint64_t frac_lsb;
+ uint64_t frac_lsbm1;
+ uint64_t round_mask;
+ uint64_t roundeven_mask;
+} FloatFmt;
+
+/* Expand fields based on the size of exponent and fraction */
+#define FLOAT_PARAMS(E, F) \
+ .exp_size = E, \
+ .exp_bias = ((1 << E) - 1) >> 1, \
+ .exp_max = (1 << E) - 1, \
+ .frac_size = F, \
+ .frac_shift = DECOMPOSED_BINARY_POINT - F, \
+ .frac_lsb = 1ull << (DECOMPOSED_BINARY_POINT - F), \
+ .frac_lsbm1 = 1ull << ((DECOMPOSED_BINARY_POINT - F) - 1), \
+ .round_mask = (1ull << (DECOMPOSED_BINARY_POINT - F)) - 1, \
+ .roundeven_mask = (2ull << (DECOMPOSED_BINARY_POINT - F)) - 1
+
+static const FloatFmt float16_params = {
+ FLOAT_PARAMS(5, 10)
+};
+
+static const FloatFmt float32_params = {
+ FLOAT_PARAMS(8, 23)
+};
+
+static const FloatFmt float64_params = {
+ FLOAT_PARAMS(11, 52)
+};
+
/*----------------------------------------------------------------------------
| Takes a 64-bit fixed-point value `absZ' with binary point between bits 6
| and 7, and returns the properly rounded 32-bit integer corresponding to the