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author | Richard Henderson <richard.henderson@linaro.org> | 2021-06-20 13:43:35 -0700 |
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committer | Richard Henderson <richard.henderson@linaro.org> | 2021-06-29 10:04:56 -0700 |
commit | 3173715195a2cb7c92e89ca478a6ee86fe9551f0 (patch) | |
tree | 3e4499aaa36a7b97ee83ee6ad48bdfc3f46cf67f /target/cris | |
parent | c96747521c5142ea3c2cba687ff09be405d4054a (diff) | |
download | qemu-3173715195a2cb7c92e89ca478a6ee86fe9551f0.zip qemu-3173715195a2cb7c92e89ca478a6ee86fe9551f0.tar.gz qemu-3173715195a2cb7c92e89ca478a6ee86fe9551f0.tar.bz2 |
target/cris: Add DISAS_DBRANCH
Move delayed branch handling to tb_stop, where we can re-use other
end-of-tb code, e.g. the evaluation of flags. Honor single stepping.
Validate that we aren't losing state by overwriting is_jmp.
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Tested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'target/cris')
-rw-r--r-- | target/cris/translate.c | 96 |
1 files changed, 56 insertions, 40 deletions
diff --git a/target/cris/translate.c b/target/cris/translate.c index a2124ff..7035426 100644 --- a/target/cris/translate.c +++ b/target/cris/translate.c @@ -61,6 +61,8 @@ #define DISAS_UPDATE DISAS_TARGET_1 /* Cpu state was modified dynamically, excluding pc -- use npc */ #define DISAS_UPDATE_NEXT DISAS_TARGET_2 +/* PC update for delayed branch, see cpustate_changed otherwise */ +#define DISAS_DBRANCH DISAS_TARGET_3 /* Used by the decoder. */ #define EXTRACT_FIELD(src, start, end) \ @@ -3230,50 +3232,22 @@ static void cris_tr_translate_insn(DisasContextBase *dcbase, CPUState *cs) dc->cpustate_changed |= dc->flags_x != (dc->base.tb->flags & X_FLAG); /* - * Check for delayed branches here. If we do it before - * actually generating any host code, the simulator will just - * loop doing nothing for on this program location. + * All branches are delayed branches, handled immediately below. + * We don't expect to see odd combinations of exit conditions. */ - if (dc->delayed_branch && --dc->delayed_branch == 0) { - if (dc->base.tb->flags & 7) { - t_gen_movi_env_TN(dslot, 0); - } - - if (dc->cpustate_changed) { - cris_store_direct_jmp(dc); - } - - if (dc->clear_locked_irq) { - dc->clear_locked_irq = 0; - t_gen_movi_env_TN(locked_irq, 0); - } + assert(dc->base.is_jmp == DISAS_NEXT || dc->cpustate_changed); - if (dc->jmp == JMP_DIRECT_CC) { - TCGLabel *l1 = gen_new_label(); - cris_evaluate_flags(dc); + if (dc->delayed_branch && --dc->delayed_branch == 0) { + dc->base.is_jmp = DISAS_DBRANCH; + return; + } - /* Conditional jmp. */ - tcg_gen_brcondi_tl(TCG_COND_EQ, env_btaken, 0, l1); - gen_goto_tb(dc, 1, dc->jmp_pc); - gen_set_label(l1); - gen_goto_tb(dc, 0, dc->pc); - dc->base.is_jmp = DISAS_NORETURN; - dc->jmp = JMP_NOJMP; - } else if (dc->jmp == JMP_DIRECT) { - cris_evaluate_flags(dc); - gen_goto_tb(dc, 0, dc->jmp_pc); - dc->base.is_jmp = DISAS_NORETURN; - dc->jmp = JMP_NOJMP; - } else { - TCGv c = tcg_const_tl(dc->pc); - t_gen_cc_jmp(env_btarget, c); - tcg_temp_free(c); - dc->base.is_jmp = DISAS_JUMP; - } + if (dc->base.is_jmp != DISAS_NEXT) { + return; } /* Force an update if the per-tb cpu state has changed. */ - if (dc->base.is_jmp == DISAS_NEXT && dc->cpustate_changed) { + if (dc->cpustate_changed) { dc->base.is_jmp = DISAS_UPDATE_NEXT; return; } @@ -3283,8 +3257,7 @@ static void cris_tr_translate_insn(DisasContextBase *dcbase, CPUState *cs) * If we can detect the length of the next insn easily, we should. * In the meantime, simply stop when we do cross. */ - if (dc->base.is_jmp == DISAS_NEXT - && ((dc->pc ^ dc->base.pc_first) & TARGET_PAGE_MASK) != 0) { + if ((dc->pc ^ dc->base.pc_first) & TARGET_PAGE_MASK) { dc->base.is_jmp = DISAS_TOO_MANY; } } @@ -3314,6 +3287,49 @@ static void cris_tr_tb_stop(DisasContextBase *dcbase, CPUState *cpu) cris_evaluate_flags(dc); + /* Evaluate delayed branch destination and fold to another is_jmp case. */ + if (is_jmp == DISAS_DBRANCH) { + if (dc->base.tb->flags & 7) { + t_gen_movi_env_TN(dslot, 0); + } + + switch (dc->jmp) { + case JMP_DIRECT: + npc = dc->jmp_pc; + is_jmp = dc->cpustate_changed ? DISAS_UPDATE_NEXT : DISAS_TOO_MANY; + break; + + case JMP_DIRECT_CC: + /* + * Use a conditional branch if either taken or not-taken path + * can use goto_tb. If neither can, then treat it as indirect. + */ + if (likely(!dc->base.singlestep_enabled) + && likely(!dc->cpustate_changed) + && (use_goto_tb(dc, dc->jmp_pc) || use_goto_tb(dc, npc))) { + TCGLabel *not_taken = gen_new_label(); + + tcg_gen_brcondi_tl(TCG_COND_EQ, env_btaken, 0, not_taken); + gen_goto_tb(dc, 1, dc->jmp_pc); + gen_set_label(not_taken); + + /* not-taken case handled below. */ + is_jmp = DISAS_TOO_MANY; + break; + } + tcg_gen_movi_tl(env_btarget, dc->jmp_pc); + /* fall through */ + + case JMP_INDIRECT: + t_gen_cc_jmp(env_btarget, tcg_constant_tl(npc)); + is_jmp = dc->cpustate_changed ? DISAS_UPDATE : DISAS_JUMP; + break; + + default: + g_assert_not_reached(); + } + } + if (unlikely(dc->base.singlestep_enabled)) { switch (is_jmp) { case DISAS_TOO_MANY: |