Skip to content

R
riscv-gcc-1
Commit c1a19acb by Roger Sayle Committed by Roger Sayle
Options

real.c (do_add): Change to return a bool indicating that the result of the operation may be... 


	* real.c (do_add): Change to return a bool indicating that the
	result of the operation may be inexact due to loss of precision.
	(do_multiply): Likewise.
	(do_divide): Likewise.

From-SVN: r65980
parent 438f50c3
Showing with 59 additions and 35 deletions
gcc/ChangeLog
2003-04-22 Roger Sayle <roger@eyesopen.com>
* real.c (do_add): Change to return a bool indicating that the
result of the operation may be inexact due to loss of precision.
(do_multiply): Likewise.
(do_divide): Likewise.
2003-04-22 Geoffrey Keating <geoffk@apple.com>
Loren James Rittle <ljrittle@acm.org>
......
gcc/real.c
......@@ -115,12 +115,12 @@ static bool div_significands PARAMS ((REAL_VALUE_TYPE *,
const REAL_VALUE_TYPE *));
static void normalize PARAMS ((REAL_VALUE_TYPE *));
static void do_add PARAMS ((REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *,
static bool do_add PARAMS ((REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *,
const REAL_VALUE_TYPE *, int));
static void do_multiply PARAMS ((REAL_VALUE_TYPE *,
static bool do_multiply PARAMS ((REAL_VALUE_TYPE *,
const REAL_VALUE_TYPE *,
const REAL_VALUE_TYPE *));
static void do_divide PARAMS ((REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *,
static bool do_divide PARAMS ((REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *,
const REAL_VALUE_TYPE *));
static int do_compare PARAMS ((const REAL_VALUE_TYPE *,
const REAL_VALUE_TYPE *, int));
......@@ -563,9 +563,10 @@ normalize (r)
}
}
/* Return R = A + (SUBTRACT_P ? -B : B). */
/* Calculate R = A + (SUBTRACT_P ? -B : B). Return true if the
result may be inexact due to a loss of precision. */
static void
static bool
do_add (r, a, b, subtract_p)
REAL_VALUE_TYPE *r;
const REAL_VALUE_TYPE *a, *b;
......@@ -584,7 +585,7 @@ do_add (r, a, b, subtract_p)
case CLASS2 (rvc_zero, rvc_zero):
/* -0 + -0 = -0, -0 - +0 = -0; all other cases yield +0. */
get_zero (r, sign & !subtract_p);
return;
return false;
case CLASS2 (rvc_zero, rvc_normal):
case CLASS2 (rvc_zero, rvc_inf):
......@@ -598,7 +599,7 @@ do_add (r, a, b, subtract_p)
/* R + Inf = Inf. */
*r = *b;
r->sign = sign ^ subtract_p;
return;
return false;
case CLASS2 (rvc_normal, rvc_zero):
case CLASS2 (rvc_inf, rvc_zero):
......@@ -610,7 +611,7 @@ do_add (r, a, b, subtract_p)
case CLASS2 (rvc_inf, rvc_normal):
/* Inf + R = Inf. */
*r = *a;
return;
return false;
case CLASS2 (rvc_inf, rvc_inf):
if (subtract_p)
......@@ -619,7 +620,7 @@ do_add (r, a, b, subtract_p)
else
/* Inf + Inf = Inf. */
*r = *a;
return;
return false;
case CLASS2 (rvc_normal, rvc_normal):
break;
......@@ -649,7 +650,7 @@ do_add (r, a, b, subtract_p)
{
*r = *a;
r->sign = sign;
return;
return true;
}
inexact |= sticky_rshift_significand (&t, b, dexp);
......@@ -680,7 +681,7 @@ do_add (r, a, b, subtract_p)
if (++exp > MAX_EXP)
{
get_inf (r, sign);
return;
return true;
}
}
}
......@@ -698,11 +699,13 @@ do_add (r, a, b, subtract_p)
r->sign = 0;
else
r->sig[0] |= inexact;
return inexact;
}
/* Return R = A * B. */
/* Calculate R = A * B. Return true if the result may be inexact. */
static void
static bool
do_multiply (r, a, b)
REAL_VALUE_TYPE *r;
const REAL_VALUE_TYPE *a, *b;
......@@ -710,6 +713,7 @@ do_multiply (r, a, b)
REAL_VALUE_TYPE u, t, *rr;
unsigned int i, j, k;
int sign = a->sign ^ b->sign;
bool inexact = false;
switch (CLASS2 (a->class, b->class))
{
......@@ -718,7 +722,7 @@ do_multiply (r, a, b)
case CLASS2 (rvc_normal, rvc_zero):
/* +-0 * ANY = 0 with appropriate sign. */
get_zero (r, sign);
return;
return false;
case CLASS2 (rvc_zero, rvc_nan):
case CLASS2 (rvc_normal, rvc_nan):
......@@ -727,7 +731,7 @@ do_multiply (r, a, b)
/* ANY * NaN = NaN. */
*r = *b;
r->sign = sign;
return;
return false;
case CLASS2 (rvc_nan, rvc_zero):
case CLASS2 (rvc_nan, rvc_normal):
......@@ -735,21 +739,20 @@ do_multiply (r, a, b)
/* NaN * ANY = NaN. */
*r = *a;
r->sign = sign;
return;
return false;
case CLASS2 (rvc_zero, rvc_inf):
case CLASS2 (rvc_inf, rvc_zero):
/* 0 * Inf = NaN */
get_canonical_qnan (r, sign);
return;
return false;
case CLASS2 (rvc_inf, rvc_inf):
case CLASS2 (rvc_normal, rvc_inf):
case CLASS2 (rvc_inf, rvc_normal):
/* Inf * Inf = Inf, R * Inf = Inf */
overflow:
get_inf (r, sign);
return;
return false;
case CLASS2 (rvc_normal, rvc_normal):
break;
......@@ -799,10 +802,16 @@ do_multiply (r, a, b)
+ (b->exp - (1-j)*(HOST_BITS_PER_LONG/2)));
if (exp > MAX_EXP)
goto overflow;
{
get_inf (r, sign);
return true;
}
if (exp < -MAX_EXP)
/* Would underflow to zero, which we shouldn't bother adding. */
continue;
{
/* Would underflow to zero, which we shouldn't bother adding. */
inexact = true;
continue;
}
u.class = rvc_normal;
u.sign = 0;
......@@ -820,18 +829,20 @@ do_multiply (r, a, b)
}
normalize (&u);
do_add (rr, rr, &u, 0);
inexact |= do_add (rr, rr, &u, 0);
}
}
rr->sign = sign;
if (rr != r)
*r = t;
return inexact;
}
/* Return R = A / B. */
/* Calculate R = A / B. Return true if the result may be inexact. */
static void
static bool
do_divide (r, a, b)
REAL_VALUE_TYPE *r;
const REAL_VALUE_TYPE *a, *b;
......@@ -847,23 +858,22 @@ do_divide (r, a, b)
case CLASS2 (rvc_inf, rvc_inf):
/* Inf / Inf = NaN. */
get_canonical_qnan (r, sign);
return;
return false;
case CLASS2 (rvc_zero, rvc_normal):
case CLASS2 (rvc_zero, rvc_inf):
/* 0 / ANY = 0. */
case CLASS2 (rvc_normal, rvc_inf):
/* R / Inf = 0. */
underflow:
get_zero (r, sign);
return;
return false;
case CLASS2 (rvc_normal, rvc_zero):
/* R / 0 = Inf. */
case CLASS2 (rvc_inf, rvc_zero):
/* Inf / 0 = Inf. */
get_inf (r, sign);
return;
return false;
case CLASS2 (rvc_zero, rvc_nan):
case CLASS2 (rvc_normal, rvc_nan):
......@@ -872,7 +882,7 @@ do_divide (r, a, b)
/* ANY / NaN = NaN. */
*r = *b;
r->sign = sign;
return;
return false;
case CLASS2 (rvc_nan, rvc_zero):
case CLASS2 (rvc_nan, rvc_normal):
......@@ -880,13 +890,12 @@ do_divide (r, a, b)
/* NaN / ANY = NaN. */
*r = *a;
r->sign = sign;
return;
return false;
case CLASS2 (rvc_inf, rvc_normal):
/* Inf / R = Inf. */
overflow:
get_inf (r, sign);
return;
return false;
case CLASS2 (rvc_normal, rvc_normal):
break;
......@@ -905,9 +914,15 @@ do_divide (r, a, b)
exp = a->exp - b->exp + 1;
if (exp > MAX_EXP)
goto overflow;
{
get_inf (r, sign);
return true;
}
if (exp < -MAX_EXP)
goto underflow;
{
get_zero (r, sign);
return true;
}
rr->exp = exp;
inexact = div_significands (rr, a, b);
......@@ -918,6 +933,8 @@ do_divide (r, a, b)
if (rr != r)
*r = t;
return inexact;
}
/* Return a tri-state comparison of A vs B. Return NAN_RESULT if
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment