From: Richard Henderson <richard.henderson@linaro.org>
Date: Thu, 18 Aug 2022 19:07:28 +0000 (-0700)
Subject: target/riscv: Add MAX_INSN_LEN and insn_len
X-Git-Tag: v7.2.0-rc0~94^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ef6e987b64343e0dc9e8526c80ee8d27d0654549;p=thirdparty%2Fqemu.git

target/riscv: Add MAX_INSN_LEN and insn_len

These will be useful in properly ending the TB.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---

diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 38666ddc91a..a719aa6e630 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -1022,6 +1022,14 @@ static uint32_t opcode_at(DisasContextBase *dcbase, target_ulong pc)
 /* Include decoders for factored-out extensions */
 #include "decode-XVentanaCondOps.c.inc"
 
+/* The specification allows for longer insns, but not supported by qemu. */
+#define MAX_INSN_LEN  4
+
+static inline int insn_len(uint16_t first_word)
+{
+    return (first_word & 3) == 3 ? 4 : 2;
+}
+
 static void decode_opc(CPURISCVState *env, DisasContext *ctx, uint16_t opcode)
 {
     /*
@@ -1037,7 +1045,7 @@ static void decode_opc(CPURISCVState *env, DisasContext *ctx, uint16_t opcode)
     };
 
     /* Check for compressed insn */
-    if (extract16(opcode, 0, 2) != 3) {
+    if (insn_len(opcode) == 2) {
         if (!has_ext(ctx, RVC)) {
             gen_exception_illegal(ctx);
         } else {