[PATCH v4 15/16] disas/riscv: enable disassembly for compressed sspush/sspopchk

[Deepak Gupta <debug@rivosinc.com>]

sspush and sspopchk have equivalent compressed encoding taken from zcmop.
cmop.1 is sspush x1 while cmop.5 is sspopchk x5. Due to unusual encoding
for both rs1 and rs2 from space bitfield, this required a new codec.

Signed-off-by: Deepak Gupta <debug@rivosinc.com>
---
 disas/riscv.c | 19 ++++++++++++++++++-
 disas/riscv.h |  1 +
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/disas/riscv.c b/disas/riscv.c
index f1f4ffc50a..8eeaa9f843 100644
--- a/disas/riscv.c
+++ b/disas/riscv.c
@@ -980,6 +980,8 @@ typedef enum {
     rv_op_ssrdp = 949,
     rv_op_ssamoswap_w = 950,
     rv_op_ssamoswap_d = 951,
+    rv_op_c_sspush = 952,
+    rv_op_c_sspopchk = 953,
 } rv_op;
 
 /* register names */
@@ -2244,6 +2246,10 @@ const rv_opcode_data rvi_opcode_data[] = {
     { "ssrdp", rv_codec_r, rv_fmt_rd, NULL, 0, 0, 0 },
     { "ssamoswap.w", rv_codec_r_a, rv_fmt_aqrl_rd_rs2_rs1, NULL, 0, 0, 0 },
     { "ssamoswap.d", rv_codec_r_a, rv_fmt_aqrl_rd_rs2_rs1, NULL, 0, 0, 0 },
+    { "c.sspush", rv_codec_cmop_ss, rv_fmt_rs2, NULL, rv_op_sspush,
+      rv_op_sspush, 0 },
+    { "c.sspopchk", rv_codec_cmop_ss, rv_fmt_rs1, NULL, rv_op_sspopchk,
+      rv_op_sspopchk, 0 },
 };
 
 /* CSR names */
@@ -2604,7 +2610,13 @@ static void decode_inst_opcode(rv_decode *dec, rv_isa isa)
             if (dec->cfg->ext_zcmop) {
                 if ((((inst >> 2) & 0b111111) == 0b100000) &&
                     (((inst >> 11) & 0b11) == 0b0)) {
-                    op = rv_c_mop_1 + ((inst >> 8) & 0b111);
+                    unsigned int cmop_code = 0;
+                    cmop_code = ((inst >> 8) & 0b111);
+                    op = rv_c_mop_1 + cmop_code;
+                    if (dec->cfg->ext_zicfiss) {
+                        op = (cmop_code == 0) ? rv_op_c_sspush : op;
+                        op = (cmop_code == 2) ? rv_op_c_sspopchk : op;
+                    }
                     break;
                 }
             }
@@ -4923,6 +4935,11 @@ static void decode_inst_operands(rv_decode *dec, rv_isa isa)
     case rv_codec_lp:
         dec->imm = operand_lpl(inst);
         break;
+    case rv_codec_cmop_ss:
+        dec->rd = rv_ireg_zero;
+        dec->rs1 = dec->rs2 = operand_crs1(inst);
+        dec->imm = 0;
+        break;
     };
 }
 
diff --git a/disas/riscv.h b/disas/riscv.h
index 4895c5a301..6a3b371cd3 100644
--- a/disas/riscv.h
+++ b/disas/riscv.h
@@ -167,6 +167,7 @@ typedef enum {
     rv_codec_r2_imm2_imm5,
     rv_codec_fli,
     rv_codec_lp,
+    rv_codec_cmop_ss,
 } rv_codec;
 
 /* structures */
-- 
2.44.0