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tcg-arm: Convert to CONFIG_QEMU_LDST_OPTIMIZATION

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Move the slow path out of line, as the TODO's mention.
This allows the fast path to be unconditional, which can
speed up the fast path as well, depending on the core.

Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2013-03-13 15:24:33 -07:00 • committed by Aurelien Jarno
parent 302fdde73f
commit df5e0ef711
3 changed files with 247 additions and 135 deletions
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17
include/exec/exec-all.h
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@ -338,6 +338,23 @@ extern uintptr_t tci_tb_ptr;
# 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))
# elif defined(__arm__)
/* We define two insns between the return address and the branch back to
straight-line. Find and decode that branch insn. */
# define GETRA() ((uintptr_t)__builtin_return_address(0))
# define GETPC_LDST() tcg_getpc_ldst(GETRA())
static inline uintptr_t tcg_getpc_ldst(uintptr_t ra)
{
int32_t b;
ra += 8; /* skip the two insns */
b = *(int32_t *)ra; /* load the branch insn */
b = (b << 8) >> (8 - 2); /* extract the displacement */
ra += 8; /* branches are relative to pc+8 */
ra += b; /* apply the displacement */
ra -= 4; /* return a pointer into the current opcode,
not the start of the next opcode */
return ra;
}
# else
# error "CONFIG_QEMU_LDST_OPTIMIZATION needs GETPC_LDST() implementation!"
# endif