On 1/14/22 7:20 AM, Philipp Tomsich wrote:
+static inline bool always_true_p(CPURISCVState *env
__attribute__((__unused__)),
+ DisasContext *ctx
__attribute__((__unused__)))
+{
+ return true;
+}
Drop the inline; the function will be instantiated so that it can be put in the
table.
Drop the env pointer. Everything this hook should examine must be in
DisasContext.
static void decode_opc(CPURISCVState *env, DisasContext *ctx, uint16_t opcode)
{
- /* check for compressed insn */
+ /* If not handled, we'll raise an illegal instruction exception */
+ bool handled = false;
+
+ /*
+ * A table with predicate (i.e., guard) functions and decoder functions
+ * that are tested in-order until a decoder matches onto the opcode.
+ */
+ const struct {
static const.
+ bool (*guard_func)(CPURISCVState *, DisasContext *);
+ bool (*decode_func)(DisasContext *, uint32_t);
+ } decoders[] = {
+ { always_true_p, decode_insn32 },
+ };
+
+ /* Check for compressed insn */
if (extract16(opcode, 0, 2) != 3) {
if (!has_ext(ctx, RVC)) {
gen_exception_illegal(ctx);
} else {
ctx->opcode = opcode;
ctx->pc_succ_insn = ctx->base.pc_next + 2;
- if (!decode_insn16(ctx, opcode)) {
- gen_exception_illegal(ctx);
- }
+ handled = decode_insn16(ctx, opcode);
}
} else {
uint32_t opcode32 = opcode;
@@ -862,10 +880,18 @@ static void decode_opc(CPURISCVState *env, DisasContext
*ctx, uint16_t opcode)
ctx->base.pc_next + 2));
ctx->opcode = opcode32;
ctx->pc_succ_insn = ctx->base.pc_next + 4;
- if (!decode_insn32(ctx, opcode32)) {
- gen_exception_illegal(ctx);
+
+ for (size_t i = 0; i < ARRAY_SIZE(decoders); ++i) {
+ if (!decoders[i].guard_func(env, ctx))
+ continue;
+
+ if ((handled = decoders[i].decode_func(ctx, opcode32)))
Never put an assignment in an if like this.
I think it would be cleaner to just do
if (decode()) {
return;
}
and drop the handled variable entirely.
r~
