target/mips: Have gen_[d]lsa() callers add 1 to shift amount argument

Having the callee add 1 to shift amount is misleading (see the
NM_LSA case in decode_nanomips_32_48_opc() where we have to
manually substract 1). Rather have the callers pass a modified
$sa.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20241112172022.88348-4-philmd@linaro.org>

5 files changed, 8 insertions, 13 deletions

diff --git a/target/mips/tcg/micromips_translate.c.inc b/target/mips/tcg/micromips_translate.c.inc
index c479bec..8fda7c8 100644
--- a/target/mips/tcg/micromips_translate.c.inc
+++ b/target/mips/tcg/micromips_translate.c.inc
@@ -1795,7 +1795,7 @@ static void decode_micromips32_opc(CPUMIPSState *env, DisasContext *ctx)
             return;
         case LSA:
             check_insn(ctx, ISA_MIPS_R6);
-            gen_lsa(ctx, rd, rt, rs, extract32(ctx->opcode, 9, 2));
+            gen_lsa(ctx, rd, rt, rs, extract32(ctx->opcode, 9, 2) + 1);
             break;
         case ALIGN:
             check_insn(ctx, ISA_MIPS_R6);
diff --git a/target/mips/tcg/msa_translate.c b/target/mips/tcg/msa_translate.c
index 75cf80a..82b1499 100644
--- a/target/mips/tcg/msa_translate.c
+++ b/target/mips/tcg/msa_translate.c
@@ -780,7 +780,7 @@ TRANS_DF_iv(ST, trans_msa_ldst, gen_helper_msa_st);
 
 static bool trans_LSA(DisasContext *ctx, arg_r *a)
 {
-    return gen_lsa(ctx, a->rd, a->rt, a->rs, a->sa);
+    return gen_lsa(ctx, a->rd, a->rt, a->rs, a->sa + 1);
 }
 
 static bool trans_DLSA(DisasContext *ctx, arg_r *a)
@@ -788,5 +788,5 @@ static bool trans_DLSA(DisasContext *ctx, arg_r *a)
     if (TARGET_LONG_BITS != 64) {
         return false;
     }
-    return gen_dlsa(ctx, a->rd, a->rt, a->rs, a->sa);
+    return gen_dlsa(ctx, a->rd, a->rt, a->rs, a->sa + 1);
 }
diff --git a/target/mips/tcg/nanomips_translate.c.inc b/target/mips/tcg/nanomips_translate.c.inc
index 1e27414..9d4e0be 100644
--- a/target/mips/tcg/nanomips_translate.c.inc
+++ b/target/mips/tcg/nanomips_translate.c.inc
@@ -3626,12 +3626,7 @@ static int decode_nanomips_32_48_opc(CPUMIPSState *env, DisasContext *ctx)
                 gen_p_lsx(ctx, rd, rs, rt);
                 break;
             case NM_LSA:
-                /*
-                 * In nanoMIPS, the shift field directly encodes the shift
-                 * amount, meaning that the supported shift values are in
-                 * the range 0 to 3 (instead of 1 to 4 in MIPSR6).
-                 */
-                gen_lsa(ctx, rd, rt, rs, extract32(ctx->opcode, 9, 2) - 1);
+                gen_lsa(ctx, rd, rt, rs, extract32(ctx->opcode, 9, 2));
                 break;
             case NM_EXTW:
                 gen_ext(ctx, 32, rd, rs, rt, extract32(ctx->opcode, 6, 5));
diff --git a/target/mips/tcg/rel6_translate.c b/target/mips/tcg/rel6_translate.c
index 8933506..4c05662 100644
--- a/target/mips/tcg/rel6_translate.c
+++ b/target/mips/tcg/rel6_translate.c
@@ -23,7 +23,7 @@ bool trans_REMOVED(DisasContext *ctx, arg_REMOVED *a)
 
 static bool trans_LSA(DisasContext *ctx, arg_r *a)
 {
-    return gen_lsa(ctx, a->rd, a->rt, a->rs, a->sa);
+    return gen_lsa(ctx, a->rd, a->rt, a->rs, a->sa + 1);
 }
 
 static bool trans_DLSA(DisasContext *ctx, arg_r *a)
@@ -31,7 +31,7 @@ static bool trans_DLSA(DisasContext *ctx, arg_r *a)
     if (TARGET_LONG_BITS != 64) {
         return false;
     }
-    return gen_dlsa(ctx, a->rd, a->rt, a->rs, a->sa);
+    return gen_dlsa(ctx, a->rd, a->rt, a->rs, a->sa + 1);
 }
 
 static bool trans_CRC32(DisasContext *ctx, arg_special3_crc *a)
diff --git a/target/mips/tcg/translate_addr_const.c b/target/mips/tcg/translate_addr_const.c
index 6f4b39f..1d140e9 100644
--- a/target/mips/tcg/translate_addr_const.c
+++ b/target/mips/tcg/translate_addr_const.c
@@ -26,7 +26,7 @@ bool gen_lsa(DisasContext *ctx, int rd, int rt, int rs, int sa)
     t1 = tcg_temp_new();
     gen_load_gpr(t0, rs);
     gen_load_gpr(t1, rt);
-    tcg_gen_shli_tl(t0, t0, sa + 1);
+    tcg_gen_shli_tl(t0, t0, sa);
     tcg_gen_add_tl(cpu_gpr[rd], t0, t1);
     tcg_gen_ext32s_tl(cpu_gpr[rd], cpu_gpr[rd]);
     return true;
@@ -47,7 +47,7 @@ bool gen_dlsa(DisasContext *ctx, int rd, int rt, int rs, int sa)
     t1 = tcg_temp_new();
     gen_load_gpr(t0, rs);
     gen_load_gpr(t1, rt);
-    tcg_gen_shli_tl(t0, t0, sa + 1);
+    tcg_gen_shli_tl(t0, t0, sa);
     tcg_gen_add_tl(cpu_gpr[rd], t0, t1);
     return true;
 }