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tcg-arm: Avoid ldrd/strd for user-only emulation

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The arm ldrd/strd insns must cause alignment traps, whereas
at least for armv7 ldr/str must handle unaligned operations.

While this is hardly the only problem facing user-only emu,
this solves one problem for i386 on armv7 emulation.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reported-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2014-03-25 17:11:37 -04:00
parent 9c5793c503
commit 1a8e80d7e8
1 changed files with 17 additions and 4 deletions
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21
tcg/arm/tcg-target.c
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@ -60,6 +60,13 @@ static int arm_arch = __ARM_ARCH;
bool use_idiv_instructions;
#endif
/* ??? Ought to think about changing CONFIG_SOFTMMU to always defined. */
#ifdef CONFIG_SOFTMMU
# define USING_SOFTMMU 1
#else
# define USING_SOFTMMU 0
#endif
#ifndef NDEBUG
static const char * const tcg_target_reg_names[TCG_TARGET_NB_REGS] = {
"%r0",
@ -1404,7 +1411,9 @@ static inline void tcg_out_qemu_ld_index(TCGContext *s, TCGMemOp opc,
TCGReg dl = (bswap ? datahi : datalo);
TCGReg dh = (bswap ? datalo : datahi);
if (use_armv6_instructions && (dl & 1) == 0 && dh == dl + 1) {
/* Avoid ldrd for user-only emulation, to handle unaligned. */
if (USING_SOFTMMU && use_armv6_instructions
&& (dl & 1) == 0 && dh == dl + 1) {
tcg_out_ldrd_r(s, COND_AL, dl, addrlo, addend);
} else if (dl != addend) {
tcg_out_ld32_rwb(s, COND_AL, dl, addend, addrlo);
@ -1463,7 +1472,9 @@ static inline void tcg_out_qemu_ld_direct(TCGContext *s, TCGMemOp opc,
TCGReg dl = (bswap ? datahi : datalo);
TCGReg dh = (bswap ? datalo : datahi);
if (use_armv6_instructions && (dl & 1) == 0 && dh == dl + 1) {
/* Avoid ldrd for user-only emulation, to handle unaligned. */
if (USING_SOFTMMU && use_armv6_instructions
&& (dl & 1) == 0 && dh == dl + 1) {
tcg_out_ldrd_8(s, COND_AL, dl, addrlo, 0);
} else if (dl == addrlo) {
tcg_out_ld32_12(s, COND_AL, dh, addrlo, bswap ? 0 : 4);
@ -1548,12 +1559,13 @@ static inline void tcg_out_qemu_st_index(TCGContext *s, int cond, TCGMemOp opc,
}
break;
case MO_64:
/* Avoid strd for user-only emulation, to handle unaligned. */
if (bswap) {
tcg_out_bswap32(s, cond, TCG_REG_R0, datahi);
tcg_out_st32_rwb(s, cond, TCG_REG_R0, addend, addrlo);
tcg_out_bswap32(s, cond, TCG_REG_R0, datalo);
tcg_out_st32_12(s, cond, TCG_REG_R0, addend, 4);
} else if (use_armv6_instructions
} else if (USING_SOFTMMU && use_armv6_instructions
&& (datalo & 1) == 0 && datahi == datalo + 1) {
tcg_out_strd_r(s, cond, datalo, addrlo, addend);
} else {
@ -1592,12 +1604,13 @@ static inline void tcg_out_qemu_st_direct(TCGContext *s, TCGMemOp opc,
}
break;
case MO_64:
/* Avoid strd for user-only emulation, to handle unaligned. */
if (bswap) {
tcg_out_bswap32(s, COND_AL, TCG_REG_R0, datahi);
tcg_out_st32_12(s, COND_AL, TCG_REG_R0, addrlo, 0);
tcg_out_bswap32(s, COND_AL, TCG_REG_R0, datalo);
tcg_out_st32_12(s, COND_AL, TCG_REG_R0, addrlo, 4);
} else if (use_armv6_instructions
} else if (USING_SOFTMMU && use_armv6_instructions
&& (datalo & 1) == 0 && datahi == datalo + 1) {
tcg_out_strd_8(s, COND_AL, datalo, addrlo, 0);
} else {