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[Qemu-devel] [PATCH v4 1/6] include/exec/exec-all: document common exit
From: |
Alex Bennée |
Subject: |
[Qemu-devel] [PATCH v4 1/6] include/exec/exec-all: document common exit conditions |
Date: |
Thu, 13 Jul 2017 15:19:23 +0100 |
As a precursor to later patches attempt to come up with a more
concrete wording for what each of the common exit cases would be.
CC: Emilio G. Cota <address@hidden>
CC: Richard Henderson <address@hidden>
CC: Lluís Vilanova <address@hidden>
Signed-off-by: Alex Bennée <address@hidden>
Reviewed-by: Richard Henderson <address@hidden>
---
include/exec/exec-all.h | 29 ++++++++++++++++++++++++++---
1 file changed, 26 insertions(+), 3 deletions(-)
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 8096d64a1d..a23894f687 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -35,11 +35,34 @@ typedef abi_ulong tb_page_addr_t;
typedef ram_addr_t tb_page_addr_t;
#endif
-/* is_jmp field values */
+/* DisasContext is_jmp field values
+ *
+ * is_jmp starts as DISAS_NEXT. The translator will keep processing
+ * instructions until an exit condition is reached. If we reach the
+ * exit condition and is_jmp is still DISAS_NEXT (because of some
+ * other condition) we simply "jump" to the next address.
+ * The remaining exit cases are:
+ *
+ * DISAS_JUMP - Only the PC was modified dynamically (e.g computed)
+ * DISAS_TB_JUMP - Only the PC was modified statically (e.g. branch)
+ *
+ * In these cases as long as the PC is updated we can chain to the
+ * next TB either by exiting the loop or looking up the next TB via
+ * the loookup helper.
+ *
+ * DISAS_UPDATE - CPU State was modified dynamically
+ *
+ * This covers any other CPU state which necessities us exiting the
+ * TCG code to the main run-loop. Typically this includes anything
+ * that might change the interrupt state.
+ *
+ * Individual translators may define additional exit cases to deal
+ * with per-target special conditions.
+ */
#define DISAS_NEXT 0 /* next instruction can be analyzed */
#define DISAS_JUMP 1 /* only pc was modified dynamically */
-#define DISAS_UPDATE 2 /* cpu state was modified dynamically */
-#define DISAS_TB_JUMP 3 /* only pc was modified statically */
+#define DISAS_TB_JUMP 2 /* only pc was modified statically */
+#define DISAS_UPDATE 3 /* cpu state was modified dynamically */
#include "qemu/log.h"
--
2.13.0
- [Qemu-devel] [PATCH v4 0/6] arm: fixes for eret, isb and DISAS_UPDATE handling, Alex Bennée, 2017/07/13
- [Qemu-devel] [PATCH v4 6/6] target/arm: use DISAS_EXIT for eret handling, Alex Bennée, 2017/07/13
- [Qemu-devel] [PATCH v4 2/6] target/arm/translate: make DISAS_UPDATE match declared semantics, Alex Bennée, 2017/07/13
- [Qemu-devel] [PATCH v4 3/6] target/arm/translate.h: expand comment on DISAS_EXIT, Alex Bennée, 2017/07/13
- [Qemu-devel] [PATCH v4 4/6] target/arm/translate: ensure gen_goto_tb sets exit flags, Alex Bennée, 2017/07/13
- [Qemu-devel] [PATCH v4 1/6] include/exec/exec-all: document common exit conditions,
Alex Bennée <=
- [Qemu-devel] [PATCH v4 5/6] target/arm: use gen_goto_tb for ISB handling, Alex Bennée, 2017/07/13
- Re: [Qemu-devel] [PATCH v4 0/6] arm: fixes for eret, isb and DISAS_UPDATE handling, Peter Maydell, 2017/07/14