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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>
This commit is contained in:
Alexander Graf 2013-12-17 19:42:33 +00:00 committed by Peter Maydell
parent b001c8c3d6
commit 39fb730aed
3 changed files with 38 additions and 7 deletions
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29
target-arm/translate-a64.c
View File

@ -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 */

14
target-arm/translate.c
View File

@ -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;
@ -7131,7 +7135,7 @@ 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) {
@ -9148,7 +9152,7 @@ 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] */
@ -9505,7 +9509,7 @@ 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;
}
}
@ -10178,7 +10182,7 @@ 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 */

2
target-arm/translate.h
View File

@ -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 */