From patchwork Fri Apr 9 15:28:40 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: tcp/mips: Change TCG_AREG0 (fp -> s0) From: Stefan Weil X-Patchwork-Id: 49849 Message-Id: <1270826920-590-1-git-send-email-weil@mail.berlios.de> To: QEMU Developers Cc: Aurelien Jarno , Richard Henderson Date: Fri, 9 Apr 2010 17:28:40 +0200 Register fp (frame pointer) is a bad choice for compilations without optimisation, because the compiler makes heavy use of this register (so the resulting code crashes). Register s0 had been used for TCG_AREG1 in earlier releases, but was no longer used and is now free for TCG_AREG0. The resulting code works for compilations without optimisation (tested with qemu mips in qemu mips on x86 host). v2: * Remove s0 from tcg_target_callee_save_regs and add fp there. Hint from Aurelien Jarno, thanks. * Add fp to list of reserved registers. v3: * Don't add fp to list of reserved registers Thanks to Richard Henderson. * Remove s0 from tcg_target_reg_alloc_order. Cc: Aurelien Jarno Cc: Richard Henderson Signed-off-by: Stefan Weil --- dyngen-exec.h | 2 +- tcg/mips/tcg-target.c | 7 +++++-- tcg/mips/tcg-target.h | 2 +- 3 files changed, 7 insertions(+), 4 deletions(-) diff --git a/dyngen-exec.h b/dyngen-exec.h index d04eda8..0700a2d 100644 --- a/dyngen-exec.h +++ b/dyngen-exec.h @@ -59,7 +59,7 @@ extern int printf(const char *, ...); #elif defined(__hppa__) #define AREG0 "r17" #elif defined(__mips__) -#define AREG0 "fp" +#define AREG0 "s0" #elif defined(__sparc__) #ifdef CONFIG_SOLARIS #define AREG0 "g2" diff --git a/tcg/mips/tcg-target.c b/tcg/mips/tcg-target.c index f4fb615..31296fc 100644 --- a/tcg/mips/tcg-target.c +++ b/tcg/mips/tcg-target.c @@ -69,7 +69,9 @@ static const char * const tcg_target_reg_names[TCG_TARGET_NB_REGS] = { /* check if we really need so many registers :P */ static const int tcg_target_reg_alloc_order[] = { +#if 0 /* used for the global env (TCG_AREG0), so don't use it here */ TCG_REG_S0, +#endif TCG_REG_S1, TCG_REG_S2, TCG_REG_S3, @@ -1450,7 +1452,9 @@ static const TCGTargetOpDef mips_op_defs[] = { }; static int tcg_target_callee_save_regs[] = { +#if 0 /* used for the global env (TCG_AREG0), so no need to save */ TCG_REG_S0, +#endif TCG_REG_S1, TCG_REG_S2, TCG_REG_S3, @@ -1459,8 +1463,7 @@ static int tcg_target_callee_save_regs[] = { TCG_REG_S6, TCG_REG_S7, TCG_REG_GP, - /* TCG_REG_FP, */ /* currently used for the global env, so np - need to save */ + TCG_REG_FP, TCG_REG_RA, /* should be last for ABI compliance */ }; diff --git a/tcg/mips/tcg-target.h b/tcg/mips/tcg-target.h index 0292d33..0028bfa 100644 --- a/tcg/mips/tcg-target.h +++ b/tcg/mips/tcg-target.h @@ -97,7 +97,7 @@ enum { #undef TCG_TARGET_HAS_ext16u_i32 /* andi rt, rs, 0xffff */ /* Note: must be synced with dyngen-exec.h */ -#define TCG_AREG0 TCG_REG_FP +#define TCG_AREG0 TCG_REG_S0 /* guest base is supported */ #define TCG_TARGET_HAS_GUEST_BASE