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tcg-i386: Use new return-argument ld/st helpers

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Discontinue the jump-around-jump-to-jump scheme, trading it for a single
immediate move instruction.  The two extra jumps always consume 7 bytes,
whereas the immediate move is either 5 or 7 bytes depending on where the
code_gen_buffer gets located.

Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2013-07-25 07:16:52 -10:00
parent aac1fb0576
commit 401c227b0a
2 changed files with 49 additions and 67 deletions
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13
include/exec/exec-all.h
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@ -326,18 +326,9 @@ extern uintptr_t tci_tb_ptr;
(6) jump to corresponding code of the next of fast path
*/
# if defined(__i386__) || defined(__x86_64__)
/* To avoid broken disassembling, long jmp is used for embedding fast path pc,
so that the destination is the next code of fast path, though this jmp is
never executed.
call MMU helper
jmp POST_PROC (2byte) <- GETRA()
jmp NEXT_CODE (5byte)
POST_PROCESS ... <- GETRA() + 7
*/
# define GETRA() ((uintptr_t)__builtin_return_address(0))
# define GETPC_LDST() ((uintptr_t)(GETRA() + 7 + \
*(int32_t *)((void *)GETRA() + 3) - 1))
/* The return address argument for ldst is passed directly. */
# define GETPC_LDST() (abort(), 0)
# elif defined (_ARCH_PPC) && !defined (_ARCH_PPC64)
# define GETRA() ((uintptr_t)__builtin_return_address(0))
# define GETPC_LDST() ((uintptr_t) ((*(int32_t *)(GETRA() - 4)) - 1))