commit 74d022f975f22fda20c0d1fe09a3f6fc7680f64f
parent b0d27d8a019811d6a4e0c0cb7ec804ab27fcec80
Author: Bor Grošelj Simić <bor.groseljsimic@telemach.net>
Date: Fri, 28 Jan 2022 02:06:17 +0100
implement unsigned -> float casts
amd64 lacks an instruction for this so it has to be implemented with
signed -> float casts:
- Word casting is done by zero-extending the word to a long and then doing
a regular signed cast.
- Long casting is done by dividing by two with correct rounding if the
highest bit is set and casting that to float, then adding
1 to mantissa with integer addition
Diffstat:
6 files changed, 107 insertions(+), 5 deletions(-)
diff --git a/amd64/isel.c b/amd64/isel.c
@@ -201,8 +201,8 @@ selcmp(Ref arg[2], int k, int swap, Fn *fn)
static void
sel(Ins i, ANum *an, Fn *fn)
{
- Ref r0, r1;
- int x, k, kc, swap;
+ Ref r0, r1, tmp[7];
+ int x, j, k, kc, swap;
int64_t sz;
Ins *i0, *i1;
@@ -266,6 +266,47 @@ sel(Ins i, ANum *an, Fn *fn)
emit(Ocopy, Kw, TMP(RCX), r0, R);
fixarg(&i1->arg[0], argcls(&i, 0), i1, fn);
break;
+ case Ouwtof:
+ r0 = newtmp("utof", Kl, fn);
+ emit(Osltof, k, i.to, r0, R);
+ emit(Oextuw, Kl, r0, i.arg[0], R);
+ fixarg(&curi->arg[0], k, curi, fn);
+ break;
+ case Oultof:
+ /*
+ %mask =l and %arg.0, 1
+ %isbig =l shr %arg.0, 63
+ %divided =l shr %arg.0, %isbig
+ %or =l or %mask, %divided
+ %float =d sltof %or
+ %cast =l cast %float
+ %addend =l shl %isbig, 52
+ %sum =l add %cast, %addend
+ %result =d cast %sum
+ */
+ r0 = newtmp("utof", k, fn);
+ if (k == Ks)
+ kc = Kw;
+ else
+ kc = Kl;
+ for (j=0; j<4; j++)
+ tmp[j] = newtmp("utof", Kl, fn);
+ for (; j<7; j++)
+ tmp[j] = newtmp("utof", kc, fn);
+ emit(Ocast, k, i.to, tmp[6], R);
+ emit(Oadd, kc, tmp[6], tmp[4], tmp[5]);
+ emit(Oshl, kc, tmp[5], tmp[1], getcon(k == Ks ? 23 : 52, fn));
+ emit(Ocast, kc, tmp[4], r0, R);
+
+ emit(Osltof, k, r0, tmp[3], R);
+ emit(Oor, Kl, tmp[3], tmp[0], tmp[2]);
+ emit(Oshr, Kl, tmp[2], i.arg[0], tmp[1]);
+ sel(*curi++, an, fn);
+ emit(Oshr, Kl, tmp[1], i.arg[0], getcon(63, fn));
+ fixarg(&curi->arg[0], Kl, curi, fn);
+ emit(Oand, Kl, tmp[0], i.arg[0], getcon(1, fn));
+ fixarg(&curi->arg[0], Kl, curi, fn);
+ break;
case Onop:
break;
case Ostored:
diff --git a/arm64/emit.c b/arm64/emit.c
@@ -91,7 +91,9 @@ static struct {
{ Ostosi, Ka, "fcvtzs %=, %S0" },
{ Odtosi, Ka, "fcvtzs %=, %D0" },
{ Oswtof, Ka, "scvtf %=, %W0" },
+ { Ouwtof, Ka, "ucvtf %=, %W0" },
{ Osltof, Ka, "scvtf %=, %L0" },
+ { Oultof, Ka, "ucvtf %=, %L0" },
{ Ocall, Kw, "blr %L0" },
{ Oacmp, Ki, "cmp %0, %1" },
diff --git a/doc/il.txt b/doc/il.txt
@@ -698,7 +698,9 @@ or convert a floating point into an integer and vice versa.
* `stosi` -- `I(ss)`
* `dtosi` -- `I(dd)`
* `swtof` -- `F(ww)`
+ * `uwtof` -- `F(ww)`
* `sltof` -- `F(ll)`
+ * `ultof` -- `F(ll)`
Extending the precision of a temporary is done using the
`ext` family of instructions. Because QBE types do not
@@ -717,9 +719,9 @@ zero.
Converting between signed integers and floating points is
done using `stosi` (single to signed integer), `dtosi`
(double to signed integer), `swtof` (signed word to float),
-and `sltof` (signed long to float). These instructions
-only handle signed integers, conversion to and from
-unsigned types are not yet supported.
+`uwtof` (unsigned word to float), `sltof` (signed long
+to float) and `ultof` (unsigned long to float). Conversion
+from unsigned types is not yet supported.
Because of <@ Subtyping >, there is no need to have an
instruction to lower the precision of an integer temporary.
@@ -990,8 +992,10 @@ instructions unless you know exactly what you are doing.
* `extuh`
* `extuw`
* `sltof`
+ * `ultof`
* `stosi`
* `swtof`
+ * `uwtof`
* `truncd`
* <@ Cast and Copy > :
diff --git a/fold.c b/fold.c
@@ -469,7 +469,9 @@ foldflt(Con *res, int op, int w, Con *cl, Con *cr)
case Odiv: xd = ld / rd; break;
case Omul: xd = ld * rd; break;
case Oswtof: xd = (int32_t)cl->bits.i; break;
+ case Ouwtof: xd = (uint32_t)cl->bits.i; break;
case Osltof: xd = (int64_t)cl->bits.i; break;
+ case Oultof: xd = (uint64_t)cl->bits.i; break;
case Oexts: xd = cl->bits.s; break;
case Ocast: xd = ld; break;
default: die("unreachable");
@@ -486,7 +488,9 @@ foldflt(Con *res, int op, int w, Con *cl, Con *cr)
case Odiv: xs = ls / rs; break;
case Omul: xs = ls * rs; break;
case Oswtof: xs = (int32_t)cl->bits.i; break;
+ case Ouwtof: xs = (uint32_t)cl->bits.i; break;
case Osltof: xs = (int64_t)cl->bits.i; break;
+ case Oultof: xs = (uint64_t)cl->bits.i; break;
case Otruncd: xs = cl->bits.d; break;
case Ocast: xs = ls; break;
default: die("unreachable");
diff --git a/ops.h b/ops.h
@@ -98,7 +98,9 @@ O(truncd, T(e,e,d,e, e,e,x,e), 1) X(0, 0, 1)
O(stosi, T(s,s,e,e, x,x,e,e), 1) X(0, 0, 1)
O(dtosi, T(d,d,e,e, x,x,e,e), 1) X(0, 0, 1)
O(swtof, T(e,e,w,w, e,e,x,x), 1) X(0, 0, 1)
+O(uwtof, T(e,e,w,w, e,e,x,x), 1) X(0, 0, 1)
O(sltof, T(e,e,l,l, e,e,x,x), 1) X(0, 0, 1)
+O(ultof, T(e,e,l,l, e,e,x,x), 1) X(0, 0, 1)
O(cast, T(s,d,w,l, x,x,x,x), 1) X(0, 0, 1)
/* Stack Allocation */
diff --git a/test/fpcnv.ssa b/test/fpcnv.ssa
@@ -17,13 +17,62 @@ function d $ftrunc(d %f) {
ret %rt
}
+export
+function s $wtos(w %w) {
+@start
+ %rt =s uwtof %w
+ ret %rt
+}
+export
+function d $wtod(w %w) {
+@start
+ %rt =d uwtof %w
+ ret %rt
+}
+
+export
+function s $ltos(l %l) {
+@start
+ %rt =s ultof %l
+ ret %rt
+}
+export
+function d $ltod(l %l) {
+@start
+ %rt =d ultof %l
+ ret %rt
+}
+
# >>> driver
# extern float fneg(float);
# extern double ftrunc(double);
+#
+# extern float wtos(unsigned int);
+# extern double wtod(unsigned int);
+# extern float ltos(long long unsigned int);
+# extern double ltod(long long unsigned int);
+#
+# unsigned long long iin[] = { 0, 1, 16, 234987, 427386245, 0x7fff0000,
+# 0xffff0000, 23602938196141, 72259248152500195, 9589010795705032704ull,
+# 0xdcf5fbe299d0148aull, 0xffffffff00000000ull, -1 };
+#
# int main() {
+# int i;
+#
# if (fneg(1.23f) != -1.23f) return 1;
# if (ftrunc(3.1415) != 3.0) return 2;
# if (ftrunc(-1.234) != -1.0) return 3;
+#
+# for (i=0; i<sizeof(iin)/sizeof(iin[0]); i++) {
+# if (wtos(iin[i]) != (float) (unsigned int)iin[i])
+# return 4;
+# if (wtod(iin[i]) != (double)(unsigned int)iin[i])
+# return 5;
+# if (ltos(iin[i]) != (float) iin[i])
+# return 6;
+# if (ltod(iin[i]) != (double)iin[i])
+# return 7;
+# }
# return 0;
# }
# <<<
