disas/riscv: Provide infrastructure for vendor extensions

A previous patch provides a pointer to the RISCVCPUConfig data.
Let's use this to add the necessary code for vendor extensions.
This patch does not change the current behaviour, but clearly
defines how vendor extension support can be added to the disassembler.

Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
Message-Id: <20230612111034.3955227-7-christoph.muellner@vrull.eu>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

diff --git a/disas/riscv.c b/disas/riscv.c
index b6789ab92a758f910c88a9226ccbcee881456442..dc3bfb012337d869d06bac7bbf79a46c4c12e667 100644 (file)
--- a/disas/riscv.c
+++ b/disas/riscv.c
@@ -4700,9 +4700,33 @@ disasm_inst(char *buf, size_t buflen, rv_isa isa, uint64_t pc, rv_inst inst,
     rv_decode dec = { 0 };
     dec.pc = pc;
     dec.inst = inst;
-    dec.opcode_data = rvi_opcode_data;
     dec.cfg = cfg;
-    decode_inst_opcode(&dec, isa);
+
+    static const struct {
+        bool (*guard_func)(const RISCVCPUConfig *);
+        const rv_opcode_data *opcode_data;
+        void (*decode_func)(rv_decode *, rv_isa);
+    } decoders[] = {
+        { always_true_p, rvi_opcode_data, decode_inst_opcode },
+    };
+
+    for (size_t i = 0; i < ARRAY_SIZE(decoders); i++) {
+        bool (*guard_func)(const RISCVCPUConfig *) = decoders[i].guard_func;
+        const rv_opcode_data *opcode_data = decoders[i].opcode_data;
+        void (*decode_func)(rv_decode *, rv_isa) = decoders[i].decode_func;
+
+        if (guard_func(cfg)) {
+            dec.opcode_data = opcode_data;
+            decode_func(&dec, isa);
+            if (dec.op != rv_op_illegal)
+                break;
+        }
+    }
+
+    if (dec.op == rv_op_illegal) {
+        dec.opcode_data = rvi_opcode_data;
+    }
+
     decode_inst_operands(&dec, isa);
     decode_inst_decompress(&dec, isa);
     decode_inst_lift_pseudo(&dec);