target/mips: add Octeon MTP instructions
Add the MTP0, MTP1, and MTP2 forms. MTP0 loads the low Octeon3 partial-product pair from rs/rt into P[0]/P[3], MTP1 loads the middle pair into P[1]/P[4], and MTP2 loads the high pair into P[2]/P[5]. For MTP0, also set P[1] to zero for backward compatibility with Octeon2 VMULU. Legacy single-source encodings have rt encoded as $zero, so the same translator path also preserves the older Octeon behavior. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: James Hilliard <james.hilliard1@gmail.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-Id: <20260520172313.23777-20-philmd@linaro.org>
James Hilliard committed
May 8, 2026 at 10:53 UTC
55b69c355fedbf18c23a05942fea6de14358b6f4
2 files changed
+27
target/mips/tcg/octeon.decode
+4
@@ -51,6 +51,10 @@ MTM0 011100 ..... ..... 00000 00000 001000 @r2
51
MTM1 011100 ..... ..... 00000 00000 001100 @r2
52
MTM2 011100 ..... ..... 00000 00000 001101 @r2
53
54
+MTP0 011100 ..... ..... 00000 00000 001001 @r2
55
+MTP1 011100 ..... ..... 00000 00000 001010 @r2
56
+MTP2 011100 ..... ..... 00000 00000 001011 @r2
57
+
58
&saa base rt
59
@saa ...... base:5 rt:5 ................ &saa
60
SAA 011100 ..... ..... 00000 00000 011000 @saa
target/mips/tcg/octeon_translate.c
+23
@@ -241,3 +241,26 @@ static bool trans_mtm(DisasContext *ctx, arg_r2 *a, unsigned int index)
241
TRANS(MTM0, trans_mtm, 0);
242
TRANS(MTM1, trans_mtm, 1);
243
TRANS(MTM2, trans_mtm, 2);
244
+
245
+static bool trans_mtp(DisasContext *ctx, arg_r2 *a, unsigned int index)
246
+{
247
+ /*
248
+ * Octeon3 two-source MTP forms load lane index from rs and lane index + 3
249
+ * from rt. Legacy one-source forms encode rt as $zero.
250
+ */
251
+ gen_load_gpr(oct_p[index], a->rs);
252
+ gen_load_gpr(oct_p[index + 3], a->rt);
253
+
254
+ /*
255
+ * Octeon3 clears P1 with a write to P0 so that VMULU sequences remain
256
+ * backward compatible with Octeon2.
257
+ */
258
+ if (index == 0) {
259
+ tcg_gen_movi_i64(oct_p[1], 0);
260
+ }
261
+ return true;
262
+}
263
+
264
+TRANS(MTP0, trans_mtp, 0);
265
+TRANS(MTP1, trans_mtp, 1);
266
+TRANS(MTP2, trans_mtp, 2);