tcg: Document tcg_qemu_tb_exec() and provide constants for low bit uses
Document tcg_qemu_tb_exec(). In particular, its return value is a
combination of a pointer to the next translation block and some
extra information in the low two bits. Provide some #defines for
the values passed in these bits to improve code clarity.
Signed-off-by: Peter Maydell <[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Signed-off-by: Blue Swirl <[email protected]>
diff --git a/cpu-exec.c b/cpu-exec.c
index afbe497..2c6b091 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -72,7 +72,7 @@
next_tb = tcg_qemu_tb_exec(env, tb->tc_ptr);
cpu->current_tb = NULL;
- if ((next_tb & 3) == 2) {
+ if ((next_tb & TB_EXIT_MASK) == TB_EXIT_ICOUNT_EXPIRED) {
/* Restore PC. This may happen if async event occurs before
the TB starts executing. */
cpu_pc_from_tb(env, tb);
@@ -584,7 +584,8 @@
spans two pages, we cannot safely do a direct
jump. */
if (next_tb != 0 && tb->page_addr[1] == -1) {
- tb_add_jump((TranslationBlock *)(next_tb & ~3), next_tb & 3, tb);
+ tb_add_jump((TranslationBlock *)(next_tb & ~TB_EXIT_MASK),
+ next_tb & TB_EXIT_MASK, tb);
}
spin_unlock(&tcg_ctx.tb_ctx.tb_lock);
@@ -598,10 +599,10 @@
tc_ptr = tb->tc_ptr;
/* execute the generated code */
next_tb = tcg_qemu_tb_exec(env, tc_ptr);
- if ((next_tb & 3) == 2) {
+ if ((next_tb & TB_EXIT_MASK) == TB_EXIT_ICOUNT_EXPIRED) {
/* Instruction counter expired. */
int insns_left;
- tb = (TranslationBlock *)(next_tb & ~3);
+ tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK);
/* Restore PC. */
cpu_pc_from_tb(env, tb);
insns_left = env->icount_decr.u32;
