target/riscv: Merge argument decode for RVC shifti

Special handling for IMM==0 is the only difference between
RVC shifti and RVI shifti.  This can be handled with !function.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

3 files changed, 12 insertions, 53 deletions

diff --git a/target/riscv/insn16.decode b/target/riscv/insn16.decode
index d0cc778bc9..add9cf3923 100644
--- a/target/riscv/insn16.decode
+++ b/target/riscv/insn16.decode
@@ -30,7 +30,7 @@
 %imm_cb        12:s1 5:2 2:1 10:2 3:2 !function=ex_shift_1
 %imm_cj        12:s1 8:1 9:2 6:1 7:1 2:1 11:1 3:3 !function=ex_shift_1
 
-%nzuimm_6bit   12:1 2:5
+%shimm_6bit   12:1 2:5               !function=ex_rvc_shifti
 %uimm_6bit_ld 2:3 12:1 5:2           !function=ex_shift_3
 %uimm_6bit_lw 2:2 12:1 4:3           !function=ex_shift_2
 %uimm_6bit_sd 7:3 10:3               !function=ex_shift_3
@@ -94,9 +94,9 @@
     uimm_sdsp=%uimm_6bit_sd rs2=%rs2_5
 
 @c_shift        ... . .. ... ..... .. \
-                &shift rd=%rs1_3 rs1=%rs1_3 shamt=%nzuimm_6bit
+                &shift rd=%rs1_3 rs1=%rs1_3 shamt=%shimm_6bit
 @c_shift2       ... . .. ... ..... .. \
-                &shift rd=%rd rs1=%rd shamt=%nzuimm_6bit
+                &shift rd=%rd rs1=%rd shamt=%shimm_6bit
 
 @c_andi         ... . .. ... ..... .. &i imm=%imm_ci rs1=%rs1_3 rd=%rs1_3
 
@@ -114,8 +114,8 @@ addi              000 .  .....  ..... 01 @ci
 c_jal_addiw       001 .  .....  ..... 01 @ci #Note: parse rd and/or imm manually
 addi              010 .  .....  ..... 01 @c_li
 c_addi16sp_lui    011 .  .....  ..... 01 @c_addi16sp_lui # shares opc with C.LUI
-c_srli            100 . 00 ...  ..... 01 @c_shift
-c_srai            100 . 01 ...  ..... 01 @c_shift
+srli              100 . 00 ...  ..... 01 @c_shift
+srai              100 . 01 ...  ..... 01 @c_shift
 andi              100 . 10 ...  ..... 01 @c_andi
 sub               100 0 11 ... 00 ... 01 @cs_2
 xor               100 0 11 ... 01 ... 01 @cs_2
@@ -128,7 +128,7 @@ beq               110  ... ...  ..... 01 @cb_z
 bne               111  ... ...  ..... 01 @cb_z
 
 # *** RV64C Standard Extension (Quadrant 2) ***
-c_slli            000 .  .....  ..... 10 @c_shift2
+slli              000 .  .....  ..... 10 @c_shift2
 fld               001 .  .....  ..... 10 @c_ldsp
 lw                010 .  .....  ..... 10 @c_lwsp
 c_flwsp_ldsp      011 .  .....  ..... 10 @c_flwsp_ldsp #C.LDSP:RV64;C.FLWSP:RV32
diff --git a/target/riscv/insn_trans/trans_rvc.inc.c b/target/riscv/insn_trans/trans_rvc.inc.c
index e840ac40df..dbe9624e32 100644
--- a/target/riscv/insn_trans/trans_rvc.inc.c
+++ b/target/riscv/insn_trans/trans_rvc.inc.c
@@ -97,37 +97,6 @@ static bool trans_c_addi16sp_lui(DisasContext *ctx, arg_c_addi16sp_lui *a)
     return false;
 }
 
-static bool trans_c_srli(DisasContext *ctx, arg_c_srli *a)
-{
-    int shamt = a->shamt;
-    if (shamt == 0) {
-        /* For RV128 a shamt of 0 means a shift by 64 */
-        shamt = 64;
-    }
-    /* Ensure, that shamt[5] is zero for RV32 */
-    if (shamt >= TARGET_LONG_BITS) {
-        return false;
-    }
-
-    arg_srli arg = { .rd = a->rd, .rs1 = a->rd, .shamt = a->shamt };
-    return trans_srli(ctx, &arg);
-}
-
-static bool trans_c_srai(DisasContext *ctx, arg_c_srai *a)
-{
-    int shamt = a->shamt;
-    if (shamt == 0) {
-        /* For RV128 a shamt of 0 means a shift by 64 */
-        shamt = 64;
-    }
-    /* Ensure, that shamt[5] is zero for RV32 */
-    if (shamt >= TARGET_LONG_BITS) {
-        return false;
-    }
-
-    arg_srai arg = { .rd = a->rd, .rs1 = a->rd, .shamt = a->shamt };
-    return trans_srai(ctx, &arg);
-}
 
 static bool trans_c_subw(DisasContext *ctx, arg_c_subw *a)
 {
@@ -147,22 +116,6 @@ static bool trans_c_addw(DisasContext *ctx, arg_c_addw *a)
 #endif
 }
 
-static bool trans_c_slli(DisasContext *ctx, arg_c_slli *a)
-{
-    int shamt = a->shamt;
-    if (shamt == 0) {
-        /* For RV128 a shamt of 0 means a shift by 64 */
-        shamt = 64;
-    }
-    /* Ensure, that shamt[5] is zero for RV32 */
-    if (shamt >= TARGET_LONG_BITS) {
-        return false;
-    }
-
-    arg_slli arg = { .rd = a->rd, .rs1 = a->rd, .shamt = a->shamt };
-    return trans_slli(ctx, &arg);
-}
-
 static bool trans_c_flwsp_ldsp(DisasContext *ctx, arg_c_flwsp_ldsp *a)
 {
 #ifdef TARGET_RISCV32
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index b09158117f..4cdffb23a4 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -558,6 +558,12 @@ static int ex_rvc_register(DisasContext *ctx, int reg)
     return 8 + reg;
 }
 
+static int ex_rvc_shifti(DisasContext *ctx, int imm)
+{
+    /* For RV128 a shamt of 0 means a shift by 64. */
+    return imm ? imm : 64;
+}
+
 /* Include the auto-generated decoder for 32 bit insn */
 #include "decode_insn32.inc.c"