On 5/12/21 1:54 PM, matheus.fe...@eldorado.org.br wrote:
+ while (i) {
+ n = ctz64(mask);
+ if (n > i) {
+ n = i;
+ }
+
+ m = (1ll << n) - 1;
+ if (bit) {
+ right = ror64(right | (src & m), n);
+ } else {
+ left = ror64(left | (src & m), n);
+ }
+
+ src >>= n;
+ mask >>= n;
+ i -= n;
+ bit = !bit;
+ mask = ~mask;
+ }
+
+ if (bit) {
+ n = ctpop64(mask);
+ } else {
+ n = 64 - ctpop64(mask);
+ }
+
+ return left | (right >> n);
+}
This doesn't correspond to the algorithm presented in the manual. Thus this
requires lots of extra commentary.
I guess I see how you're trying to process blocks at a time, instead of single
bits at a time. But I don't think the merging of data into "right" and "left"
looks right. I would have expected
right = (right << n) | (src & m);
and similarly for left.
It doesn't look like that the ctpop at the end is correct, given how mask has
been modified. I would have thought that
n = ctpop64(orig_mask);
return (left << n) | right;
would be the correct answer.
I could be wrong about the above, but that's what the missing commentary should
have helped me understand.
+static bool trans_CFUGED(DisasContext *ctx, arg_X *a)
+{
+ REQUIRE_64BIT(ctx);
+ REQUIRE_INSNS_FLAGS2(ctx, ISA310);
+#if defined(TARGET_PPC64)
+ gen_helper_cfuged(cpu_gpr[a->ra], cpu_gpr[a->rt], cpu_gpr[a->rb]);
+#else
+ gen_invalid(ctx);
+#endif
+ return true;
+}
Given that this helper will also be used by vcfuged, there's no point in hiding
it in a TARGET_PPC64 block, and thus you can drop the ifdefs.
r~
