target/arm: Rearrange decode in disas_uncond_b_reg

This will enable PAuth decode in a subsequent patch.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20190108223129.5570-13-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Richard Henderson 2019-01-21 10:23:12 +00:00 committed by Peter Maydell
parent d9f482a027
commit f7cf3bfc1b

View File

@ -1989,32 +1989,54 @@ static void disas_uncond_b_reg(DisasContext *s, uint32_t insn)
rn = extract32(insn, 5, 5);
op4 = extract32(insn, 0, 5);
if (op4 != 0x0 || op3 != 0x0 || op2 != 0x1f) {
unallocated_encoding(s);
return;
if (op2 != 0x1f) {
goto do_unallocated;
}
switch (opc) {
case 0: /* BR */
case 1: /* BLR */
case 2: /* RET */
gen_a64_set_pc(s, cpu_reg(s, rn));
switch (op3) {
case 0:
if (op4 != 0) {
goto do_unallocated;
}
dst = cpu_reg(s, rn);
break;
default:
goto do_unallocated;
}
gen_a64_set_pc(s, dst);
/* BLR also needs to load return address */
if (opc == 1) {
tcg_gen_movi_i64(cpu_reg(s, 30), s->pc);
}
break;
case 4: /* ERET */
if (s->current_el == 0) {
unallocated_encoding(s);
return;
goto do_unallocated;
}
if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) {
gen_io_start();
switch (op3) {
case 0:
if (op4 != 0) {
goto do_unallocated;
}
dst = tcg_temp_new_i64();
tcg_gen_ld_i64(dst, cpu_env,
offsetof(CPUARMState, elr_el[s->current_el]));
break;
default:
goto do_unallocated;
}
if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) {
gen_io_start();
}
gen_helper_exception_return(cpu_env, dst);
tcg_temp_free_i64(dst);
if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) {
@ -2023,14 +2045,17 @@ static void disas_uncond_b_reg(DisasContext *s, uint32_t insn)
/* Must exit loop to check un-masked IRQs */
s->base.is_jmp = DISAS_EXIT;
return;
case 5: /* DRPS */
if (rn != 0x1f) {
unallocated_encoding(s);
if (op3 != 0 || op4 != 0 || rn != 0x1f) {
goto do_unallocated;
} else {
unsupported_encoding(s, insn);
}
return;
default:
do_unallocated:
unallocated_encoding(s);
return;
}