risc_x86.h

DOSBox emulates a full x86 pc with sound and dos. Its main use is to run old dosgames on platforms w

/*
 *  Copyright (C) 2002-2007  The DOSBox Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

static void gen_init(void);

/* End of needed */

#define X86_REGS		7
#define X86_REG_EAX		0x00
#define X86_REG_ECX		0x01
#define X86_REG_EDX		0x02
#define X86_REG_EBX		0x03
#define X86_REG_EBP		0x04
#define X86_REG_ESI		0x05
#define X86_REG_EDI		0x06

#define X86_REG_MASK(_REG_) (1 << X86_REG_ ## _REG_)

static struct {
	bool flagsactive;
	Bitu last_used;
	GenReg * regs[X86_REGS];
} x86gen;

class GenReg {
public:
	GenReg(Bit8u _index) {
		index=_index;
		notusable=false;dynreg=0;
	}
	DynReg  * dynreg;
	Bitu last_used;			//Keeps track of last assigned regs 
    Bit8u index;
	bool notusable;
	void Load(DynReg * _dynreg,bool stale=false) {
		if (!_dynreg) return;
		if (GCC_UNLIKELY((Bitu)dynreg)) Clear();
		dynreg=_dynreg;
		last_used=x86gen.last_used;
		dynreg->flags&=~DYNFLG_CHANGED;
		dynreg->genreg=this;
		if ((!stale) && (dynreg->flags & (DYNFLG_LOAD|DYNFLG_ACTIVE))) {
			cache_addw(0x058b+(index << (8+3)));		//Mov reg,[data]
			cache_addd((Bit32u)dynreg->data);
		}
		dynreg->flags|=DYNFLG_ACTIVE;
	}
	void Save(void) {
		if (GCC_UNLIKELY(!((Bitu)dynreg))) IllegalOption("GenReg->Save");
		dynreg->flags&=~DYNFLG_CHANGED;
		cache_addw(0x0589+(index << (8+3)));		//Mov [data],reg
		cache_addd((Bit32u)dynreg->data);
	}
	void Release(void) {
		if (GCC_UNLIKELY(!((Bitu)dynreg))) return;
		if (dynreg->flags&DYNFLG_CHANGED && dynreg->flags&DYNFLG_SAVE) {
			Save();
		}
		dynreg->flags&=~(DYNFLG_CHANGED|DYNFLG_ACTIVE);
		dynreg->genreg=0;dynreg=0;
	}
	void Clear(void) {
		if (!dynreg) return;
		if (dynreg->flags&DYNFLG_CHANGED) {
			Save();
		}
		dynreg->genreg=0;dynreg=0;
	}
};

static BlockReturn gen_runcode(Bit8u * code) {
	BlockReturn retval;
#if defined (_MSC_VER)
	__asm {
/* Prepare the flags */
		mov		eax,[code]
		push	ebx
		push	ebp
		push	esi
		push	edi
		mov		ebx,[reg_flags]
		and		ebx,FMASK_TEST
		push	offset(return_address)
		push	ebx
		jmp		eax
/* Restore the flags */
return_address:
		/*	return here with flags in ecx */
		and		dword ptr [reg_flags],~FMASK_TEST
		and		ecx,FMASK_TEST
		or		[reg_flags],ecx
		pop		edi
		pop		esi
		pop		ebp
		pop		ebx
		mov		[retval],eax
	}
#elif defined (MACOSX)
	register Bit32u tempflags=reg_flags & FMASK_TEST;
	__asm__ volatile (
		"pushl %%ebx						\n"
		"pushl %%ebp						\n"
		"pushl $(run_return_adress)			\n"
		"pushl  %2							\n"
		"jmp  *%3							\n"
		"run_return_adress:					\n"
		"popl %%ebp							\n"
		"popl %%ebx							\n"
		:"=a" (retval), "=c" (tempflags)
		:"r" (tempflags),"r" (code)
		:"%edx","%edi","%esi","cc","memory"
	);
	reg_flags=(reg_flags & ~FMASK_TEST) | (tempflags & FMASK_TEST);
#else
	register Bit32u tempflags=reg_flags & FMASK_TEST;
	__asm__ volatile (
		"pushl %%ebp						\n"
		"pushl $(run_return_adress)			\n"
		"pushl  %2							\n"
		"jmp  *%3							\n"
		"run_return_adress:					\n"
		"popl %%ebp							\n"
		:"=a" (retval), "=c" (tempflags)
		:"r" (tempflags),"r" (code)
		:"%edx","%ebx","%edi","%esi","cc","memory"
	);
	reg_flags=(reg_flags & ~FMASK_TEST) | (tempflags & FMASK_TEST);
#endif
	return retval;
}

static GenReg * FindDynReg(DynReg * dynreg,bool stale=false) {
	x86gen.last_used++;
	if (dynreg->genreg) {
		dynreg->genreg->last_used=x86gen.last_used;
		return dynreg->genreg;
	}
	/* Find best match for selected global reg */
	Bits i;
	Bits first_used,first_index;
	first_used=-1;
	if (dynreg->flags & DYNFLG_HAS8) {
		/* Has to be eax,ebx,ecx,edx */
		for (i=first_index=0;i<=X86_REG_EBX;i++) {
			GenReg * genreg=x86gen.regs[i];
			if (genreg->notusable) continue;
			if (!(genreg->dynreg)) {
				genreg->Load(dynreg,stale);
				return genreg;
			}
			if (genreg->last_used<first_used) {
				first_used=genreg->last_used;
				first_index=i;
			}
		}
	} else {
		for (i=first_index=X86_REGS-1;i>=0;i--) {
			GenReg * genreg=x86gen.regs[i];
			if (genreg->notusable) continue;
			if (!(genreg->dynreg)) {
				genreg->Load(dynreg,stale);
				return genreg;
			}
			if (genreg->last_used<first_used) {
				first_used=genreg->last_used;
				first_index=i;
			}
		}
	}
	/* No free register found use earliest assigned one */
	GenReg * newreg=x86gen.regs[first_index];
	newreg->Load(dynreg,stale);
	return newreg;
}

static GenReg * ForceDynReg(GenReg * genreg,DynReg * dynreg) {
	genreg->last_used=++x86gen.last_used;
	if (dynreg->genreg==genreg) return genreg;
	if (genreg->dynreg) genreg->Clear();
	if (dynreg->genreg) dynreg->genreg->Clear();
	genreg->Load(dynreg);
	return genreg;
}

static void gen_preloadreg(DynReg * dynreg) {
	FindDynReg(dynreg);
}

static void gen_releasereg(DynReg * dynreg) {
	GenReg * genreg=dynreg->genreg;
	if (genreg) genreg->Release();
	else dynreg->flags&=~(DYNFLG_ACTIVE|DYNFLG_CHANGED);
}

static void gen_setupreg(DynReg * dnew,DynReg * dsetup) {
	dnew->flags=dsetup->flags;
	if (dnew->genreg==dsetup->genreg) return;
	/* Not the same genreg must be wrong */
	if (dnew->genreg) {
		/* Check if the genreg i'm changing is actually linked to me */
		if (dnew->genreg->dynreg==dnew) dnew->genreg->dynreg=0;
	}
	dnew->genreg=dsetup->genreg;
	if (dnew->genreg) dnew->genreg->dynreg=dnew;
}

static void gen_synchreg(DynReg * dnew,DynReg * dsynch) {
	/* First make sure the registers match */
	if (dnew->genreg!=dsynch->genreg) {
		if (dnew->genreg) dnew->genreg->Clear();
		if (dsynch->genreg) {
			dsynch->genreg->Load(dnew);
		}
	}
	/* Always use the loadonce flag from either state */
	dnew->flags|=(dsynch->flags & dnew->flags&DYNFLG_ACTIVE);
	if ((dnew->flags ^ dsynch->flags) & DYNFLG_CHANGED) {
		/* Ensure the changed value gets saved */	
		if (dnew->flags & DYNFLG_CHANGED) {
			dnew->genreg->Save();
		} else dnew->flags|=DYNFLG_CHANGED;
	}
}

static void gen_needflags(void) {
	if (!x86gen.flagsactive) {
		x86gen.flagsactive=true;
		cache_addb(0x9d);		//POPFD
	}
}

static void gen_protectflags(void) {
	if (x86gen.flagsactive) {
		x86gen.flagsactive=false;
		cache_addb(0x9c);		//PUSHFD
	}
}

static void gen_discardflags(void) {
	if (!x86gen.flagsactive) {
		x86gen.flagsactive=true;
		cache_addw(0xc483);		//ADD ESP,4
		cache_addb(0x4);
	}
}

static void gen_needcarry(void) {
	if (!x86gen.flagsactive) {
		x86gen.flagsactive=true;
		cache_addw(0x2cd1);			//SHR DWORD [ESP],1
		cache_addb(0x24);
		cache_addd(0x0424648d);		//LEA ESP,[ESP+4]
	}
}

static bool skip_flags=false;

static void set_skipflags(bool state) {
	if (!state) gen_discardflags();
	skip_flags=state;
}

static void gen_reinit(void) {
	x86gen.last_used=0;
	x86gen.flagsactive=false;
	for (Bitu i=0;i<X86_REGS;i++) {
		x86gen.regs[i]->dynreg=0;
	}
}


static void gen_load_host(void * data,DynReg * dr1,Bitu size) {
	GenReg * gr1=FindDynReg(dr1,true);
	switch (size) {
	case 1:cache_addw(0xb60f);break;	//movzx byte
	case 2:cache_addw(0xb70f);break;	//movzx word
	case 4:cache_addb(0x8b);break;	//mov
	default:
		IllegalOption("gen_load_host");
	}
	cache_addb(0x5+(gr1->index<<3));
	cache_addd((Bit32u)data);
	dr1->flags|=DYNFLG_CHANGED;
}

static void gen_mov_host(void * data,DynReg * dr1,Bitu size,Bit8u di1=0) {
	GenReg * gr1=FindDynReg(dr1,(size==4));
	switch (size) {
	case 1:cache_addb(0x8a);break;	//mov byte
	case 2:cache_addb(0x66);		//mov word
	case 4:cache_addb(0x8b);break;	//mov
	default:
		IllegalOption("gen_load_host");
	}
	cache_addb(0x5+((gr1->index+(di1?4:0))<<3));
	cache_addd((Bit32u)data);
	dr1->flags|=DYNFLG_CHANGED;
}


static void gen_dop_byte(DualOps op,DynReg * dr1,Bit8u di1,DynReg * dr2,Bit8u di2) {
	GenReg * gr1=FindDynReg(dr1);GenReg * gr2=FindDynReg(dr2);
	Bit8u tmp;
	switch (op) {
	case DOP_ADD:	tmp=0x02; break;
	case DOP_ADC:	tmp=0x12; break;
	case DOP_SUB:	tmp=0x2a; break;
	case DOP_SBB:	tmp=0x1a; break;
	case DOP_CMP:	tmp=0x3a; goto nochange;
	case DOP_XOR:	tmp=0x32; break;
	case DOP_AND:	tmp=0x22; if ((dr1==dr2) && (di1==di2)) goto nochange; break;
	case DOP_OR:	tmp=0x0a; if ((dr1==dr2) && (di1==di2)) goto nochange; break;
	case DOP_TEST:	tmp=0x84; goto nochange;
	case DOP_MOV:	if ((dr1==dr2) && (di1==di2)) return; tmp=0x8a; break;
	case DOP_XCHG:	tmp=0x86; dr2->flags|=DYNFLG_CHANGED; break;
	default:
		IllegalOption("gen_dop_byte");
	}
	dr1->flags|=DYNFLG_CHANGED;
nochange:
	cache_addw(tmp|(0xc0+((gr1->index+di1)<<3)+gr2->index+di2)<<8);
}

static void gen_dop_byte_imm(DualOps op,DynReg * dr1,Bit8u di1,Bitu imm) {
	GenReg * gr1=FindDynReg(dr1);
	Bit16u tmp;
	switch (op) {
	case DOP_ADD:	tmp=0xc080; break;
	case DOP_ADC:	tmp=0xd080; break;
	case DOP_SUB:	tmp=0xe880; break;
	case DOP_SBB:	tmp=0xd880; break;
	case DOP_CMP:	tmp=0xf880; goto nochange;	//Doesn't change
	case DOP_XOR:	tmp=0xf080; break;
	case DOP_AND:	tmp=0xe080; break;
	case DOP_OR:	tmp=0xc880; break;
	case DOP_TEST:	tmp=0xc0f6; goto nochange;	//Doesn't change
	case DOP_MOV:	cache_addb(0xb0+gr1->index+di1);
					dr1->flags|=DYNFLG_CHANGED;
					goto finish;
	default:
		IllegalOption("gen_dop_byte_imm");
	}
	dr1->flags|=DYNFLG_CHANGED;
nochange:
	cache_addw(tmp+((gr1->index+di1)<<8));
finish:
	cache_addb(imm);
}

static void gen_dop_byte_imm_mem(DualOps op,DynReg * dr1,Bit8u di1,void* data) {
	GenReg * gr1=FindDynReg(dr1);
	Bit16u tmp;
	switch (op) {
	case DOP_ADD:	tmp=0x0502; break;
	case DOP_ADC:	tmp=0x0512; break;
	case DOP_SUB:	tmp=0x052a; break;
	case DOP_SBB:	tmp=0x051a; break;
	case DOP_CMP:	tmp=0x053a; goto nochange;	//Doesn't change
	case DOP_XOR:	tmp=0x0532; break;
	case DOP_AND:	tmp=0x0522; break;
	case DOP_OR:	tmp=0x050a; break;
	case DOP_TEST:	tmp=0x0584; goto nochange;	//Doesn't change
	case DOP_MOV:	tmp=0x0585; break;
	default:
		IllegalOption("gen_dop_byte_imm_mem");
	}
	dr1->flags|=DYNFLG_CHANGED;
nochange:
	cache_addw(tmp+((gr1->index+di1)<<11));
	cache_addd((Bit32u)data);
}

static void gen_sop_byte(SingleOps op,DynReg * dr1,Bit8u di1) {
	GenReg * gr1=FindDynReg(dr1);
	Bit16u tmp;
	switch (op) {
	case SOP_INC: tmp=0xc0FE; break;
	case SOP_DEC: tmp=0xc8FE; break;
	case SOP_NOT: tmp=0xd0f6; break;
	case SOP_NEG: tmp=0xd8f6; break;
	default:
		IllegalOption("gen_sop_byte");
	}
	cache_addw(tmp + ((gr1->index+di1)<<8));
	dr1->flags|=DYNFLG_CHANGED;
}


static void gen_extend_word(bool sign,DynReg * ddr,DynReg * dsr) {
	GenReg * gsr=FindDynReg(dsr);
	GenReg * gdr=FindDynReg(ddr,true);
	if (sign) cache_addw(0xbf0f);
	else cache_addw(0xb70f);
	cache_addb(0xc0+(gdr->index<<3)+(gsr->index));
	ddr->flags|=DYNFLG_CHANGED;
}

static void gen_extend_byte(bool sign,bool dword,DynReg * ddr,DynReg * dsr,Bit8u dsi) {
	GenReg * gsr=FindDynReg(dsr);
	GenReg * gdr=FindDynReg(ddr,dword);
	if (!dword) cache_addb(0x66);
	if (sign) cache_addw(0xbe0f);
	else cache_addw(0xb60f);
	cache_addb(0xc0+(gdr->index<<3)+(gsr->index+dsi));
	ddr->flags|=DYNFLG_CHANGED;
}

static void gen_lea(DynReg * ddr,DynReg * dsr1,DynReg * dsr2,Bitu scale,Bits imm) {
	GenReg * gdr=FindDynReg(ddr);
	Bitu imm_size;
	Bit8u rm_base=(gdr->index << 3);
	if (dsr1) {
		GenReg * gsr1=FindDynReg(dsr1);
		if (!imm && (gsr1->index!=0x5)) {
			imm_size=0;	rm_base+=0x0;			//no imm
		} else if ((imm>=-128 && imm<=127)) {
			imm_size=1;rm_base+=0x40;			//Signed byte imm
		} else {
			imm_size=4;rm_base+=0x80;			//Signed dword imm
		}
		if (dsr2) {
			GenReg * gsr2=FindDynReg(dsr2);
			cache_addb(0x8d);		//LEA
			cache_addb(rm_base+0x4);			//The sib indicator
			Bit8u sib=(gsr1->index)+(gsr2->index<<3)+(scale<<6);
			cache_addb(sib);
		} else {
			if ((ddr==dsr1) && !imm_size) return;
			cache_addb(0x8d);		//LEA
			cache_addb(rm_base+gsr1->index);
		}
	} else {
		if (dsr2) {
			GenReg * gsr2=FindDynReg(dsr2);
			cache_addb(0x8d);			//LEA
			cache_addb(rm_base+0x4);	//The sib indicator
			Bit8u sib=(5+(gsr2->index<<3)+(scale<<6));
			cache_addb(sib);
			imm_size=4;
		} else {
			cache_addb(0x8d);			//LEA
			cache_addb(rm_base+0x05);	//dword imm
			imm_size=4;
		}
	}
	switch (imm_size) {
	case 0:	break;
	case 1:cache_addb(imm);break;
	case 4:cache_addd(imm);break;
	}
	ddr->flags|=DYNFLG_CHANGED;
}

static void gen_lea_imm_mem(DynReg * ddr,DynReg * dsr,void* data) {
	GenReg * gdr=FindDynReg(ddr);
	Bit8u rm_base=(gdr->index << 3);
	cache_addw(0x058b+(rm_base<<8));
	cache_addd((Bit32u)data);
	GenReg * gsr=FindDynReg(dsr);
	cache_addb(0x8d);		//LEA
	cache_addb(rm_base+0x44);
	cache_addb(rm_base+gsr->index);
	cache_addb(0x00);
	ddr->flags|=DYNFLG_CHANGED;
}

static void gen_dop_word(DualOps op,bool dword,DynReg * dr1,DynReg * dr2) {
	GenReg * gr2=FindDynReg(dr2);
	GenReg * gr1=FindDynReg(dr1,dword && op==DOP_MOV);
	Bit8u tmp;
	switch (op) {
	case DOP_ADD:	tmp=0x03; break;
	case DOP_ADC:	tmp=0x13; break;
	case DOP_SUB:	tmp=0x2b; break;
	case DOP_SBB:	tmp=0x1b; break;
	case DOP_CMP:	tmp=0x3b; goto nochange;
	case DOP_XOR:	tmp=0x33; break;
	case DOP_AND:	tmp=0x23; if (dr1==dr2) goto nochange; break;
	case DOP_OR:	tmp=0x0b; if (dr1==dr2) goto nochange; break;
	case DOP_TEST:	tmp=0x85; goto nochange;
	case DOP_MOV:	if (dr1==dr2) return; tmp=0x8b; break;
	case DOP_XCHG:
		dr2->flags|=DYNFLG_CHANGED;
		if (dword && !((dr1->flags&DYNFLG_HAS8) ^ (dr2->flags&DYNFLG_HAS8))) {
			dr1->genreg=gr2;dr1->genreg->dynreg=dr1;
			dr2->genreg=gr1;dr2->genreg->dynreg=dr2;
			dr1->flags|=DYNFLG_CHANGED;
			return;
		}
		tmp=0x87;
		break;
	default:
		IllegalOption("gen_dop_word");
	}
	dr1->flags|=DYNFLG_CHANGED;
nochange:
	if (!dword) cache_addb(0x66);
	cache_addw(tmp|(0xc0+(gr1->index<<3)+gr2->index)<<8);
}

static void gen_dop_word_imm(DualOps op,bool dword,DynReg * dr1,Bits imm) {
	GenReg * gr1=FindDynReg(dr1,dword && op==DOP_MOV);
	Bit16u tmp;
	if (!dword) cache_addb(0x66);
	switch (op) {
	case DOP_ADD:	tmp=0xc081; break; 
	case DOP_ADC:	tmp=0xd081; break;
	case DOP_SUB:	tmp=0xe881; break;
	case DOP_SBB:	tmp=0xd881; break;
	case DOP_CMP:	tmp=0xf881; goto nochange;	//Doesn't change
	case DOP_XOR:	tmp=0xf081; break;
	case DOP_AND:	tmp=0xe081; break;
	case DOP_OR:	tmp=0xc881; break;
	case DOP_TEST:	tmp=0xc0f7; goto nochange;	//Doesn't change