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authorAlexander Graf <agraf@suse.de>2013-12-03 15:12:18 +0000
committerPeter Maydell <peter.maydell@linaro.org>2013-12-05 21:29:13 +0000
commit23f0e4df3def8cad9eb4dbfe40aa514726293684 (patch)
tree3b88ec9c876442c916b1dd3df7ce044edd6e2ca9
parentbc54173a4c479a5c29ab6179b8d9b6b69366560f (diff)
downloadqemu-arm-23f0e4df3def8cad9eb4dbfe40aa514726293684.tar.gz
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>
-rw-r--r--target-arm/translate-a64.c29
-rw-r--r--target-arm/translate.c14
-rw-r--r--target-arm/translate.h2
3 files changed, 38 insertions, 7 deletions
diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
index ce2f841e36..a6a1973dd7 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 */
diff --git a/target-arm/translate.c b/target-arm/translate.c
index 553bdedfc1..9e2d1eb5b3 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -671,7 +671,11 @@ static void gen_thumb2_parallel_addsub(int op1, int op2, TCGv_i32 a, TCGv_i32 b)
}
#undef PAS_OP
-static void gen_test_cc(int cc, int label)
+/*
+ * generate a conditional branch based on ARM condition code cc.
+ * This is common between ARM and Aarch64 targets.
+ */
+void arm_gen_test_cc(int cc, int label)
{
TCGv_i32 tmp;
int inv;
@@ -6903,7 +6907,7 @@ static void disas_arm_insn(CPUARMState * env, DisasContext *s)
/* if not always execute, we generate a conditional jump to
next instruction */
s->condlabel = gen_new_label();
- gen_test_cc(cond ^ 1, s->condlabel);
+ arm_gen_test_cc(cond ^ 1, s->condlabel);
s->condjmp = 1;
}
if ((insn & 0x0f900000) == 0x03000000) {
@@ -8910,7 +8914,7 @@ static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw
op = (insn >> 22) & 0xf;
/* Generate a conditional jump to next instruction. */
s->condlabel = gen_new_label();
- gen_test_cc(op ^ 1, s->condlabel);
+ arm_gen_test_cc(op ^ 1, s->condlabel);
s->condjmp = 1;
/* offset[11:1] = insn[10:0] */
@@ -9267,7 +9271,7 @@ static void disas_thumb_insn(CPUARMState *env, DisasContext *s)
cond = s->condexec_cond;
if (cond != 0x0e) { /* Skip conditional when condition is AL. */
s->condlabel = gen_new_label();
- gen_test_cc(cond ^ 1, s->condlabel);
+ arm_gen_test_cc(cond ^ 1, s->condlabel);
s->condjmp = 1;
}
}
@@ -9940,7 +9944,7 @@ static void disas_thumb_insn(CPUARMState *env, DisasContext *s)
}
/* generate a conditional jump to next instruction */
s->condlabel = gen_new_label();
- gen_test_cc(cond ^ 1, s->condlabel);
+ arm_gen_test_cc(cond ^ 1, s->condlabel);
s->condjmp = 1;
/* jump to the offset */
diff --git a/target-arm/translate.h b/target-arm/translate.h
index 23a45daff8..a6f6b3e699 100644
--- a/target-arm/translate.h
+++ b/target-arm/translate.h
@@ -65,4 +65,6 @@ static inline void gen_a64_set_pc_im(uint64_t val)
}
#endif
+void arm_gen_test_cc(int cc, int label);
+
#endif /* TARGET_ARM_TRANSLATE_H */