more tarval cleanup

[r21396]

ir/common/firm.c

@@ -114,7 +114,7 @@ void init_firm(const firm_parameter_t *param)
 	/* create the type kinds. */
 	init_tpop();
 	/* create an obstack and put all tarvals in a pdeq */
-	init_tarval_1(0l);
+	init_tarval_1(0l, /* support_quad_precision */0);
 	/* Builds a basic program representation, so modes can be added. */
 	init_irprog_1();
 	/* initialize all modes an ir node can consist of */

ir/tv/fltcalc.c

@@ -52,7 +52,7 @@
 
 #include "xmalloc.h"
 
-/** The number of extra precesion rounding bits */
+/** The number of extra precision rounding bits */
 #define ROUNDING_BITS 2
 
 typedef uint32_t UINT32;
@@ -1531,11 +1531,11 @@ void init_fltcalc(int precision) {
 		/* does nothing if already init */
 		if (precision == 0) precision = FC_DEFAULT_PRECISION;
 
-		init_strcalc(precision + 4);
+		init_strcalc(precision + 2 + ROUNDING_BITS);
 
-		/* needs additionally two bits to round, a bit as explicit 1., and one for
+		/* needs additionally rounding bits, one bit as explicit 1., and one for
 		 * addition overflow */
-		max_precision = sc_get_precision() - 4;
+		max_precision = sc_get_precision() - (2 + ROUNDING_BITS);
 		if (max_precision < precision)
 			printf("WARNING: not enough precision available, using %d\n", max_precision);
 

ir/tv/tv.c

@@ -1756,7 +1756,7 @@ static const tarval_mode_info hex_output = {
 /*
  * Initialization of the tarval module: called before init_mode()
  */
-void init_tarval_1(long null_value) {
+void init_tarval_1(long null_value, int support_quad_precision) {
 	/* if these assertion fail, tarval_is_constant() will follow ... */
 	assert(tarval_b_false == &reserved_tv[0] && "b_false MUST be the first reserved tarval!");
 	assert(tarval_b_true  == &reserved_tv[1] && "b_true MUST be the second reserved tarval!");
@@ -1767,10 +1767,8 @@ void init_tarval_1(long null_value) {
 	 * an initial size, which is the expected number of constants */
 	tarvals = new_set(cmp_tv, N_CONSTANTS);
 	values  = new_set(memcmp, N_CONSTANTS);
-	/* init strcalc with precision of 68 to support floating point values with 64
-	 * bit mantissa (needs extra bits for rounding and overflow) */
-	init_strcalc(68);
-	init_fltcalc(0);
+	/* calls init_strcalc() with needed size */
+	init_fltcalc(support_quad_precision ? 112 : 64);
 }
 
 /*

ir/tv/tv_t.h

@@ -50,9 +50,12 @@ enum reserved_id {
  *
  * Call before init_mode().
  *
- * @param null_value  The reference mode NULL value, typical 0l
+ * @param null_value
+ *            The reference mode NULL value, typical 0l
+ * @param support_quad_precision
+ *            If non-zero, activate support for quad precision
  */
-void init_tarval_1(long null_value);
+void init_tarval_1(long null_value, int support_quad_precision);
 
 /**
  * Initialization of the tarval module.