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target-arm: A64: add support for 'test and branch' imm

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This patch adds emulation for the test and branch insns,
TBZ and TBNZ.

Signed-off-by: Alexander Graf <agraf@suse.de>
[claudio:
  adapted for new decoder
  always compare with 0
  remove a TCG temporary
]
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>
This commit is contained in:
Alexander Graf 2013-12-17 19:42:33 +00:00 committed by Peter Maydell
parent 39fb730aed
commit db0f79589c
1 changed files with 25 additions and 2 deletions
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27
target-arm/translate-a64.c
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@ -233,10 +233,33 @@ static void disas_comp_b_imm(DisasContext *s, uint32_t insn)
unsupported_encoding(s, insn);
}
/* Test & branch (immediate) */
/* C3.2.5 Test & branch (immediate)
* 31 30 25 24 23 19 18 5 4 0
* +----+-------------+----+-------+-------------+------+
* | b5 | 0 1 1 0 1 1 | op | b40 | imm14 | Rt |
* +----+-------------+----+-------+-------------+------+
*/
static void disas_test_b_imm(DisasContext *s, uint32_t insn)
{
unsupported_encoding(s, insn);
unsigned int bit_pos, op, rt;
uint64_t addr;
int label_match;
TCGv_i64 tcg_cmp;
bit_pos = (extract32(insn, 31, 1) << 5) | extract32(insn, 19, 5);
op = extract32(insn, 24, 1); /* 0: TBZ; 1: TBNZ */
addr = s->pc + sextract32(insn, 5, 14) * 4 - 4;
rt = extract32(insn, 0, 5);
tcg_cmp = tcg_temp_new_i64();
tcg_gen_andi_i64(tcg_cmp, cpu_reg(s, rt), (1ULL << bit_pos));
label_match = gen_new_label();
tcg_gen_brcondi_i64(op ? TCG_COND_NE : TCG_COND_EQ,
tcg_cmp, 0, label_match);
tcg_temp_free_i64(tcg_cmp);
gen_goto_tb(s, 0, s->pc);
gen_set_label(label_match);
gen_goto_tb(s, 1, addr);
}
/* C3.2.2 / C5.6.19 Conditional branch (immediate)