Re: [Qemu-devel] SH: Implement MOVCO.L and MOVLI.L

[Aurelien Jarno <aurelien@aurel32.net>]

On Thu, Feb 19, 2009 at 11:12:04PM +0300, Vladimir Prus wrote:
> On Friday 13 February 2009 23:11:05 Aurelien Jarno wrote:
> > On Thu, Feb 12, 2009 at 12:05:15AM +0300, Vladimir Prus wrote:
> > > On Saturday 07 February 2009 17:24:59 Aurelien Jarno wrote:
> > > > On Thu, Dec 11, 2008 at 09:48:00PM +0300, Vladimir Prus wrote:
> > > > > On Thursday 11 December 2008 21:36:13 Paul Brook wrote:
> > > > > > On Thursday 11 December 2008, Vladimir Prus wrote:
> > > > > > > This patch implements a couple more instructions
> > > > > > > specific to SH4A. 
> > > > > > 
> > > > > > > +          For now, do unconditional move. FIXME.
> > > > > > 
> > > > > > I can't make sense of this FIXME.
> > > > > 
> > > > > At it happens, it's stale. The entire line you quoted can be removed.
> > > > > I attach the revised patch.
> > > > > 
> > > > > - Volodya
> > > > > 
> > > > > 
> > > > 
> > > > > commit 9ba7a6294a809dc11a0348ccca501513dd90ae6e
> > > > > Author: Vladimir Prus <vladimir@codesourcery.com>
> > > > > Date:   Sun Oct 12 19:36:22 2008 +0400
> > > > > 
> > > > >     SH: Implement MOVCO.L and MOVLI.L
> > > > >     
> > > > >     	* target-sh4/cpu.h (struct CPUSH4State): New field ldst.
> > > > >     	* target-sh4/helper.c (do_interrupt): Initialize ldst.
> > > > >     	* target-sh4/translate.c (cpu_ldst): New.
> > > > >     	(sh4_translate_init): Initialize cpu_ldst.
> > > > >     	(_decode_opc): Support MOVCO.L and MOVLI.L.
> > > > > 
> > > > > diff --git a/target-sh4/cpu.h b/target-sh4/cpu.h
> > > > > index a0108b4..ae434d1 100644
> > > > > --- a/target-sh4/cpu.h
> > > > > +++ b/target-sh4/cpu.h
> > > > > @@ -135,6 +135,8 @@ typedef struct CPUSH4State {
> > > > >      uint32_t prr;		/* Processor Revision Register */
> > > > >      uint32_t cvr;		/* Cache Version Register */
> > > > >  
> > > > > +    uint32_t ldst;
> > > > > +
> > > > >       CPU_COMMON tlb_t utlb[UTLB_SIZE];	/* unified translation table */
> > > > >      tlb_t itlb[ITLB_SIZE];	/* instruction translation table */
> > > > >      void *intc_handle;
> > > > > diff --git a/target-sh4/helper.c b/target-sh4/helper.c
> > > > > index 882bc9c..61b668b 100644
> > > > > --- a/target-sh4/helper.c
> > > > > +++ b/target-sh4/helper.c
> > > > > @@ -160,6 +160,7 @@ void do_interrupt(CPUState * env)
> > > > >      env->spc = env->pc;
> > > > >      env->sgr = env->gregs[15];
> > > > >      env->sr |= SR_BL | SR_MD | SR_RB;
> > > > > +    env->ldst = 0;
> > > > >  
> > > > >      if (env->flags & (DELAY_SLOT | DELAY_SLOT_CONDITIONAL)) {
> > > > >          /* Branch instruction should be executed again before delay slot. */
> > > > > diff --git a/target-sh4/translate.c b/target-sh4/translate.c
> > > > > index d38e95f..e4a1b28 100644
> > > > > --- a/target-sh4/translate.c
> > > > > +++ b/target-sh4/translate.c
> > > > > @@ -72,7 +72,7 @@ static TCGv_ptr cpu_env;
> > > > >  static TCGv cpu_gregs[24];
> > > > >  static TCGv cpu_pc, cpu_sr, cpu_ssr, cpu_spc, cpu_gbr;
> > > > >  static TCGv cpu_vbr, cpu_sgr, cpu_dbr, cpu_mach, cpu_macl;
> > > > > -static TCGv cpu_pr, cpu_fpscr, cpu_fpul;
> > > > > +static TCGv cpu_pr, cpu_fpscr, cpu_fpul, cpu_ldst;
> > > > >  static TCGv cpu_fregs[32];
> > > > >  
> > > > >  /* internal register indexes */
> > > > > @@ -144,6 +144,8 @@ static void sh4_translate_init(void)
> > > > >      cpu_delayed_pc = tcg_global_mem_new_i32(TCG_AREG0,
> > > > >  					    offsetof(CPUState, delayed_pc),
> > > > >  					    "_delayed_pc_");
> > > > > +    cpu_ldst = tcg_global_mem_new_i32(TCG_AREG0,
> > > > > +				      offsetof(CPUState, ldst), "_ldst_");
> > > > >  
> > > > >      for (i = 0; i < 32; i++)
> > > > >          cpu_fregs[i] = tcg_global_mem_new_i32(TCG_AREG0,
> > > > > @@ -1543,6 +1545,36 @@ static void _decode_opc(DisasContext * ctx)
> > > > >      case 0x0029:		/* movt Rn */
> > > > >  	tcg_gen_andi_i32(REG(B11_8), cpu_sr, SR_T);
> > > > >  	return;
> > > > > +    case 0x0073:
> > > > > +        /* MOVCO.L 
> > > > > +	       LDST -> T
> > > > > +               If (T == 1) R0 -> (Rn)
> > > > > +               0 -> LDST
> > > > > +        */	   
> > > > > +        if (ctx->features & SH_FEATURE_SH4A) {
> > > > > +	    int label = gen_new_label();
> > > > > +	    gen_clr_t();
> > > > > +	    tcg_gen_or_i32(cpu_sr, cpu_sr, cpu_ldst);
> > > > > +	    tcg_gen_brcondi_i32(TCG_COND_EQ, cpu_ldst, 0, label);
> > > > > +	    tcg_gen_qemu_st32(REG(0), REG(B11_8), ctx->memidx);
> > > > > +	    gen_set_label(label);
> > > > > +	    tcg_gen_movi_i32(cpu_ldst, 0);
> > > > > +	    return;
> > > > > +	} else
> > > > > +	    break;
> > > > > +    case 0x0063:
> > > > > +        /* MOVLI.L @Rm,R0 
> > > > > +               1 -> LDST
> > > > > +               (Rm) -> R0
> > > > > +               When interrupt/exception
> > > > > +               occurred 0 -> LDST
> > > > > +        */     
> > > > > +	if (ctx->features & SH_FEATURE_SH4A) {
> > > > > +	    tcg_gen_movi_i32(cpu_ldst, 1);
> > > > > +	    tcg_gen_qemu_ld32s(REG(0), REG(B11_8), ctx->memidx);
> > > > > +	    return;
> > > > 
> > > > This TCG code doesn't seems to match the comments. With the current
> > > > code, if a load exception occurs, LDST end with a value of 1 instead of
> > > > 0.
> > > 
> > > I might be missing something -- it was my intention that if any exception
> > > or interrupt happens, do_interrupt will set ldst to zero. And if the exception
> > > happens during load, there's nothing else that will set ldst back to 1. Did
> > > I miss something?
> > > 
> > 
> > In system mode, I am not sure that doing that in do_interrupt() is the
> > best way, especially given it looks like we can exit this subroutine
> > before actually setting the value to 0, though I haven't really analyzed
> > those cases. In user mode, it's surely wrong, given that do_interrupt()
> > does nothing.
> > 
> > In my opinion you should use the fact that the TCG code will stop it's
> > execution at the point were the exception occurs. Doing something like
> > this should work:
> > 
> > tcg_gen_movi_i32(cpu_ldst, 0);
> > tcg_gen_qemu_ld32s(REG(0), REG(B11_8), ctx->memidx);
> > tcg_gen_movi_i32(cpu_ldst, 1);
> > 
> > This way if everything works fine, cpu_ldst ends with 1. If an exception
> > occurs, it stays to zero.
> 
> Here's a patch implementing this idea -- it appears to still work
> fine with 7785.
> 
> - Volodya

Thanks, applied.

> commit a49011d4d2aeebd6b4da93b3fd1a80e2f031cd85
> Author: Vladimir Prus <vladimir@codesourcery.com>
> Date:   Sun Oct 12 19:36:22 2008 +0400
> 
>     SH: Implement MOVCO.L and MOVLI.L
>     
>     	* target-sh4/cpu.h (struct CPUSH4State): New field ldst.
>     	* target-sh4/translate.c (cpu_ldst): New.
>     	(sh4_translate_init): Initialize cpu_ldst.
>     	(_decode_opc): Support MOVCO.L and MOVLI.L.
> 
> diff --git a/target-sh4/cpu.h b/target-sh4/cpu.h
> index 86a4a6b..7ee22d8 100644
> --- a/target-sh4/cpu.h
> +++ b/target-sh4/cpu.h
> @@ -140,6 +140,8 @@ typedef struct CPUSH4State {
>      uint32_t prr;		/* Processor Revision Register */
>      uint32_t cvr;		/* Cache Version Register */
>  
> +    uint32_t ldst;
> +
>       CPU_COMMON tlb_t utlb[UTLB_SIZE];	/* unified translation table */
>      tlb_t itlb[ITLB_SIZE];	/* instruction translation table */
>      void *intc_handle;
> diff --git a/target-sh4/translate.c b/target-sh4/translate.c
> index a0ee4f1..e0bd54b 100644
> --- a/target-sh4/translate.c
> +++ b/target-sh4/translate.c
> @@ -72,7 +72,7 @@ static TCGv_ptr cpu_env;
>  static TCGv cpu_gregs[24];
>  static TCGv cpu_pc, cpu_sr, cpu_ssr, cpu_spc, cpu_gbr;
>  static TCGv cpu_vbr, cpu_sgr, cpu_dbr, cpu_mach, cpu_macl;
> -static TCGv cpu_pr, cpu_fpscr, cpu_fpul;
> +static TCGv cpu_pr, cpu_fpscr, cpu_fpul, cpu_ldst;
>  static TCGv cpu_fregs[32];
>  
>  /* internal register indexes */
> @@ -144,6 +144,8 @@ static void sh4_translate_init(void)
>      cpu_delayed_pc = tcg_global_mem_new_i32(TCG_AREG0,
>  					    offsetof(CPUState, delayed_pc),
>  					    "_delayed_pc_");
> +    cpu_ldst = tcg_global_mem_new_i32(TCG_AREG0,
> +				      offsetof(CPUState, ldst), "_ldst_");
>  
>      for (i = 0; i < 32; i++)
>          cpu_fregs[i] = tcg_global_mem_new_i32(TCG_AREG0,
> @@ -1559,6 +1561,37 @@ static void _decode_opc(DisasContext * ctx)
>      case 0x0029:		/* movt Rn */
>  	tcg_gen_andi_i32(REG(B11_8), cpu_sr, SR_T);
>  	return;
> +    case 0x0073:
> +        /* MOVCO.L 
> +	       LDST -> T
> +               If (T == 1) R0 -> (Rn)
> +               0 -> LDST
> +        */	   
> +        if (ctx->features & SH_FEATURE_SH4A) {
> +	    int label = gen_new_label();
> +	    gen_clr_t();
> +	    tcg_gen_or_i32(cpu_sr, cpu_sr, cpu_ldst);
> +	    tcg_gen_brcondi_i32(TCG_COND_EQ, cpu_ldst, 0, label);
> +	    tcg_gen_qemu_st32(REG(0), REG(B11_8), ctx->memidx);
> +	    gen_set_label(label);
> +	    tcg_gen_movi_i32(cpu_ldst, 0);
> +	    return;
> +	} else
> +	    break;
> +    case 0x0063:
> +        /* MOVLI.L @Rm,R0 
> +               1 -> LDST
> +               (Rm) -> R0
> +               When interrupt/exception
> +               occurred 0 -> LDST
> +        */     
> +	if (ctx->features & SH_FEATURE_SH4A) {
> +	    tcg_gen_movi_i32(cpu_ldst, 0);
> +	    tcg_gen_qemu_ld32s(REG(0), REG(B11_8), ctx->memidx);
> +	    tcg_gen_movi_i32(cpu_ldst, 1);
> +	    return;
> +	} else
> +	    break;
>      case 0x0093:		/* ocbi @Rn */
>  	{
>  	    TCGv dummy = tcg_temp_new();


-- 
Aurelien Jarno	                        GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net