diff options
| author | Alex Bennée <alex.bennee@linaro.org> | 2017-07-17 13:36:07 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2017-07-17 13:36:07 +0100 |
| commit | df0311e634828fdc99ca59352aef68503d631aad (patch) | |
| tree | 8abd3ded45fcb5321aad40ed5c88179694f0605c | |
| parent | 8d92e26b452f8961ec90df3f93cf5f3b7a9d158f (diff) | |
include/exec/exec-all: document common exit conditions
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 <cota@braap.org>
CC: Richard Henderson <rth@twiddle.net>
CC: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-id: 20170713141928.25419-2-alex.bennee@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| -rw-r--r-- | include/exec/exec-all.h | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h index bf8da2aa5a..6b6e28791e 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" |