@@ -10,6 +10,7 @@ DEF_HELPER_FLAGS_1(cttz, TCG_CALL_NO_RWG_SE, i64, i64)
DEF_HELPER_FLAGS_2(zap, TCG_CALL_NO_RWG_SE, i64, i64, i64)
DEF_HELPER_FLAGS_2(zapnot, TCG_CALL_NO_RWG_SE, i64, i64, i64)
+DEF_HELPER_FLAGS_1(cmpbe0, TCG_CALL_NO_RWG_SE, i64, i64)
DEF_HELPER_FLAGS_2(cmpbge, TCG_CALL_NO_RWG_SE, i64, i64, i64)
DEF_HELPER_FLAGS_2(minub8, TCG_CALL_NO_RWG_SE, i64, i64, i64)
@@ -58,6 +58,20 @@ uint64_t helper_zap(uint64_t val, uint64_t mask)
return helper_zapnot(val, ~mask);
}
+uint64_t helper_cmpbe0(uint64_t a)
+{
+ uint64_t m = 0x7f7f7f7f7f7f7f7fULL;
+ uint64_t c = ~(((a & m) + m) | a | m);
+ /* a.......b.......c.......d.......e.......f.......g.......h....... */
+ c |= c << 7;
+ /* ab......bc......cd......de......ef......fg......gh......h....... */
+ c |= c << 14;
+ /* abcd....bcde....cdef....defg....efgh....fgh.....gh......h....... */
+ c |= c << 28;
+ /* abcdefghbcdefgh.cdefgh..defgh...efgh....fgh.....gh......h....... */
+ return c >> 56;
+}
+
uint64_t helper_cmpbge(uint64_t a, uint64_t b)
{
uint64_t mask = 0x00ff00ff00ff00ffULL;
@@ -1507,7 +1507,12 @@ static ExitStatus translate_one(DisasContext *ctx, uint32_t insn)
break;
case 0x0F:
/* CMPBGE */
- gen_helper_cmpbge(vc, va, vb);
+ if (ra == 31) {
+ /* Special case 0 >= X as X == 0. */
+ gen_helper_cmpbe0(vc, vb);
+ } else {
+ gen_helper_cmpbge(vc, va, vb);
+ }
break;
case 0x12:
/* S8ADDL */
Knowing the comparator is zero leads to a simpler operation. Signed-off-by: Richard Henderson <rth@twiddle.net> --- target-alpha/helper.h | 1 + target-alpha/int_helper.c | 14 ++++++++++++++ target-alpha/translate.c | 7 ++++++- 3 files changed, 21 insertions(+), 1 deletion(-)