diff options
| author | Alexander Graf <agraf@suse.de> | 2013-12-17 19:42:33 +0000 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2013-12-17 19:42:33 +0000 |
| commit | 39fb730aed8c5f7b0058845cb9feac0d4b177985 (patch) | |
| tree | 82ec795502c06f01ffe0dc99e9c9fbe4daf49631 /target-arm/translate-a64.c | |
| parent | b001c8c3d6855b0b52fc0fdd63b5a93fd326bf0c (diff) | |
target-arm: A64: add support for conditional branches
This patch adds emulation for the conditional branch (b.cond) instruction.
Signed-off-by: Alexander Graf <agraf@suse.de>
[claudio: adapted to new decoder structure,
reused arm infrastructure for checking the flags]
Signed-off-by: Claudio Fontana <claudio.fontana@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'target-arm/translate-a64.c')
| -rw-r--r-- | target-arm/translate-a64.c | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c index b69466585f..4eb2992754 100644 --- a/target-arm/translate-a64.c +++ b/target-arm/translate-a64.c @@ -239,10 +239,35 @@ static void disas_test_b_imm(DisasContext *s, uint32_t insn) unsupported_encoding(s, insn); } -/* Conditional branch (immediate) */ +/* C3.2.2 / C5.6.19 Conditional branch (immediate) + * 31 25 24 23 5 4 3 0 + * +---------------+----+---------------------+----+------+ + * | 0 1 0 1 0 1 0 | o1 | imm19 | o0 | cond | + * +---------------+----+---------------------+----+------+ + */ static void disas_cond_b_imm(DisasContext *s, uint32_t insn) { - unsupported_encoding(s, insn); + unsigned int cond; + uint64_t addr; + + if ((insn & (1 << 4)) || (insn & (1 << 24))) { + unallocated_encoding(s); + return; + } + addr = s->pc + sextract32(insn, 5, 19) * 4 - 4; + cond = extract32(insn, 0, 4); + + if (cond < 0x0e) { + /* genuinely conditional branches */ + int label_match = gen_new_label(); + arm_gen_test_cc(cond, label_match); + gen_goto_tb(s, 0, s->pc); + gen_set_label(label_match); + gen_goto_tb(s, 1, addr); + } else { + /* 0xe and 0xf are both "always" conditions */ + gen_goto_tb(s, 0, addr); + } } /* C5.6.68 HINT */ |