decoder.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.
 */

#define X86_DYNFPU_DH_ENABLED
#define X86_INLINED_MEMACCESS


enum REP_Type {
	REP_NONE=0,REP_NZ,REP_Z
};

static struct DynDecode {
	PhysPt code;
	PhysPt code_start;
	PhysPt op_start;
	bool big_op;
	bool big_addr;
	REP_Type rep;
	Bitu cycles;
	CacheBlock * block;
	CacheBlock * active_block;
	struct {
		CodePageHandler * code;	
		Bitu index;
		Bit8u * wmap;
		Bit8u * invmap;
		Bitu first;
	} page;
	struct {
		Bitu val;
		Bitu mod;
		Bitu rm;
		Bitu reg;
	} modrm;
	DynReg * segprefix;
} decode;

static bool MakeCodePage(Bitu lin_page,CodePageHandler * &cph) {
	Bit8u rdval;
	//Ensure page contains memory:
	if (GCC_UNLIKELY(mem_readb_checked_x86(lin_page << 12,&rdval))) return true;
	PageHandler * handler=paging.tlb.handler[lin_page];
	if (handler->flags & PFLAG_HASCODE) {
		cph=( CodePageHandler *)handler;
		return false;
	}
	if (handler->flags & PFLAG_NOCODE) {
		LOG_MSG("DYNX86:Can't run code in this page");
		cph=0;		return false;
	} 
	Bitu phys_page=lin_page;
	if (!PAGING_MakePhysPage(phys_page)) {
		LOG_MSG("DYNX86:Can't find physpage");
		cph=0;		return false;
	}
	/* Find a free CodePage */
	if (!cache.free_pages) {
		if (cache.used_pages!=decode.page.code) cache.used_pages->ClearRelease();
		else {
			if ((cache.used_pages->next) && (cache.used_pages->next!=decode.page.code))
				cache.used_pages->next->ClearRelease();
			else {
				LOG_MSG("DYNX86:Invalid cache links");
				cache.used_pages->ClearRelease();
			}
		}
	}
	CodePageHandler * cpagehandler=cache.free_pages;
	cache.free_pages=cache.free_pages->next;
	cpagehandler->prev=cache.last_page;
	cpagehandler->next=0;
	if (cache.last_page) cache.last_page->next=cpagehandler;
	cache.last_page=cpagehandler;
	if (!cache.used_pages) cache.used_pages=cpagehandler;
	cpagehandler->SetupAt(phys_page,handler);
	MEM_SetPageHandler(phys_page,1,cpagehandler);
	PAGING_UnlinkPages(lin_page,1);
	cph=cpagehandler;
	return false;
}

static Bit8u decode_fetchb(void) {
	if (GCC_UNLIKELY(decode.page.index>=4096)) {
        /* Advance to the next page */
		decode.active_block->page.end=4095;
		/* trigger possible page fault here */
		mem_readb((++decode.page.first) << 12);
		MakeCodePage(decode.page.first,decode.page.code);
		CacheBlock * newblock=cache_getblock();
		decode.active_block->crossblock=newblock;
		newblock->crossblock=decode.active_block;
		decode.active_block=newblock;
		decode.active_block->page.start=0;
		decode.page.code->AddCrossBlock(decode.active_block);
		decode.page.wmap=decode.page.code->write_map;
		decode.page.invmap=decode.page.code->invalidation_map;
		decode.page.index=0;
	}
	decode.page.wmap[decode.page.index]+=0x01;
	decode.page.index++;
	decode.code+=1;
	return mem_readb(decode.code-1);
}
static Bit16u decode_fetchw(void) {
	if (GCC_UNLIKELY(decode.page.index>=4095)) {
   		Bit16u val=decode_fetchb();
		val|=decode_fetchb() << 8;
		return val;
	}
	*(Bit16u *)&decode.page.wmap[decode.page.index]+=0x0101;
	decode.code+=2;decode.page.index+=2;
	return mem_readw(decode.code-2);
}
static Bit32u decode_fetchd(void) {
	if (GCC_UNLIKELY(decode.page.index>=4093)) {
   		Bit32u val=decode_fetchb();
		val|=decode_fetchb() << 8;
		val|=decode_fetchb() << 16;
		val|=decode_fetchb() << 24;
		return val;
        /* Advance to the next page */
	}
	*(Bit32u *)&decode.page.wmap[decode.page.index]+=0x01010101;
	decode.code+=4;decode.page.index+=4;
	return mem_readd(decode.code-4);
}

#define START_WMMEM 64

static void INLINE decode_increase_wmapmask(Bitu size) {
	Bitu mapidx;
	CacheBlock* activecb=decode.active_block; 
	if (GCC_UNLIKELY(!activecb->cache.wmapmask)) {
		activecb->cache.wmapmask=(Bit8u*)malloc(START_WMMEM);
		memset(activecb->cache.wmapmask,0,START_WMMEM);
		activecb->cache.maskstart=decode.page.index;
		activecb->cache.masklen=START_WMMEM;
		mapidx=0;
	} else {
		mapidx=decode.page.index-activecb->cache.maskstart;
		if (GCC_UNLIKELY(mapidx+size>=activecb->cache.masklen)) {
			Bitu newmasklen=activecb->cache.masklen*4;
			if (newmasklen<mapidx+size) newmasklen=((mapidx+size)&~3)*2;
			Bit8u* tempmem=(Bit8u*)malloc(newmasklen);
			memset(tempmem,0,newmasklen);
			memcpy(tempmem,activecb->cache.wmapmask,activecb->cache.masklen);
			free(activecb->cache.wmapmask);
			activecb->cache.wmapmask=tempmem;
			activecb->cache.masklen=newmasklen;
		}
	}
	switch (size) {
		case 1 : activecb->cache.wmapmask[mapidx]+=0x01; break;
		case 2 : (*(Bit16u*)&activecb->cache.wmapmask[mapidx])+=0x0101; break;
		case 4 : (*(Bit32u*)&activecb->cache.wmapmask[mapidx])+=0x01010101; break;
	}
}

static bool decode_fetchb_imm(Bitu & val) {
	if (decode.page.index<4096) {
		Bitu index=(decode.code>>12);
		if (paging.tlb.read[index]) {
			val=(Bitu)(paging.tlb.read[index]+decode.code);
			decode_increase_wmapmask(1);
			decode.code++;
			decode.page.index++;
			return true;
		}
	}
	val=(Bit32u)decode_fetchb();
	return false;
}
static bool decode_fetchw_imm(Bitu & val) {
	if (decode.page.index<4095) {
		Bitu index=(decode.code>>12);
		if (paging.tlb.read[index]) {
			val=(Bitu)(paging.tlb.read[index]+decode.code);
			decode_increase_wmapmask(2);
			decode.code+=2;
			decode.page.index+=2;
			return true;
		}
	}
	val=decode_fetchw();
	return false;
}
static bool decode_fetchd_imm(Bitu & val) {
	if (decode.page.index<4093) {
		Bitu index=(decode.code>>12);
		if (paging.tlb.read[index]) {
			val=(Bitu)(paging.tlb.read[index]+decode.code);
			decode_increase_wmapmask(4);
			decode.code+=4;
			decode.page.index+=4;
			return true;
		}
	}
	val=decode_fetchd();
	return false;
}


static void dyn_reduce_cycles(void) {
	gen_protectflags();
	if (!decode.cycles) decode.cycles++;
	gen_dop_word_imm(DOP_SUB,true,DREG(CYCLES),decode.cycles);
}

static void dyn_save_noncritical_regs(void) {
	gen_releasereg(DREG(EAX));
	gen_releasereg(DREG(ECX));
	gen_releasereg(DREG(EDX));
	gen_releasereg(DREG(EBX));
	gen_releasereg(DREG(ESP));
	gen_releasereg(DREG(EBP));
	gen_releasereg(DREG(ESI));
	gen_releasereg(DREG(EDI));
}

static void dyn_save_critical_regs(void) {
	dyn_save_noncritical_regs();
	gen_releasereg(DREG(FLAGS));
	gen_releasereg(DREG(EIP));
	gen_releasereg(DREG(CYCLES));
}

static void dyn_set_eip_last_end(DynReg * endreg) {
	gen_protectflags();
	gen_lea(endreg,DREG(EIP),0,0,decode.code-decode.code_start);
	gen_dop_word_imm(DOP_ADD,decode.big_op,DREG(EIP),decode.op_start-decode.code_start);
}

static INLINE void dyn_set_eip_end(void) {
	gen_protectflags();
	gen_dop_word_imm(DOP_ADD,cpu.code.big,DREG(EIP),decode.code-decode.code_start);
}

static INLINE void dyn_set_eip_end(DynReg * endreg) {
	gen_protectflags();
	gen_dop_word(DOP_MOV,cpu.code.big,DREG(TMPW),DREG(EIP));
	gen_dop_word_imm(DOP_ADD,cpu.code.big,DREG(TMPW),decode.code-decode.code_start);
}

static INLINE void dyn_set_eip_last(void) {
	gen_protectflags();
	gen_dop_word_imm(DOP_ADD,cpu.code.big,DREG(EIP),decode.op_start-decode.code_start);
}


enum save_info_type {exception, cycle_check, normal, fpu_restore};


static struct {
	save_info_type type;
	DynState state;
	Bit8u * branch_pos;
	Bit32u eip_change;
	Bitu cycles;
	Bit8u * return_pos;
} save_info[512];

Bitu used_save_info=0;


static BlockReturn DynRunException(Bit32u eip_add,Bit32u cycle_sub,Bit32u dflags) {
	reg_flags=(dflags&FMASK_TEST) | (reg_flags&(~FMASK_TEST));
	reg_eip+=eip_add;
	CPU_Cycles-=cycle_sub;
	if (cpu.exception.which==SMC_CURRENT_BLOCK) return BR_SMCBlock;
	CPU_Exception(cpu.exception.which,cpu.exception.error);
	return BR_Normal;
}

static void dyn_check_bool_exception(DynReg * check) {
	gen_dop_byte(DOP_OR,check,0,check,0);
	save_info[used_save_info].branch_pos=gen_create_branch_long(BR_NZ);
	dyn_savestate(&save_info[used_save_info].state);
	if (!decode.cycles) decode.cycles++;
	save_info[used_save_info].cycles=decode.cycles;
	save_info[used_save_info].eip_change=decode.op_start-decode.code_start;
	if (!cpu.code.big) save_info[used_save_info].eip_change&=0xffff;
	save_info[used_save_info].type=exception;
	used_save_info++;
}

static void dyn_check_bool_exception_al(void) {
	cache_addw(0xc00a);		// or al, al
	save_info[used_save_info].branch_pos=gen_create_branch_long(BR_NZ);
	dyn_savestate(&save_info[used_save_info].state);
	if (!decode.cycles) decode.cycles++;
	save_info[used_save_info].cycles=decode.cycles;
	save_info[used_save_info].eip_change=decode.op_start-decode.code_start;
	if (!cpu.code.big) save_info[used_save_info].eip_change&=0xffff;
	save_info[used_save_info].type=exception;
	used_save_info++;
}

#include "pic.h"

static void dyn_check_irqrequest(void) {
	gen_load_host(&PIC_IRQCheck,DREG(TMPB),4);
	gen_dop_word(DOP_OR,true,DREG(TMPB),DREG(TMPB));
	save_info[used_save_info].branch_pos=gen_create_branch_long(BR_NZ);
	gen_releasereg(DREG(TMPB));
	dyn_savestate(&save_info[used_save_info].state);
	if (!decode.cycles) decode.cycles++;
	save_info[used_save_info].cycles=decode.cycles;
	save_info[used_save_info].eip_change=decode.code-decode.code_start;
	if (!cpu.code.big) save_info[used_save_info].eip_change&=0xffff;
	save_info[used_save_info].type=normal;
	used_save_info++;
}

static void dyn_check_bool_exception_ne(void) {
	save_info[used_save_info].branch_pos=gen_create_branch_long(BR_Z);
	dyn_savestate(&save_info[used_save_info].state);
	if (!decode.cycles) decode.cycles++;
	save_info[used_save_info].cycles=decode.cycles;
	save_info[used_save_info].eip_change=decode.op_start-decode.code_start;
	if (!cpu.code.big) save_info[used_save_info].eip_change&=0xffff;
	save_info[used_save_info].type=exception;
	used_save_info++;
}

static void dyn_fill_blocks(void) {
	for (Bitu sct=0; sct<used_save_info; sct++) {
		gen_fill_branch_long(save_info[sct].branch_pos);
		switch (save_info[sct].type) {
			case exception:
				dyn_loadstate(&save_info[sct].state);
				decode.cycles=save_info[sct].cycles;
				dyn_save_critical_regs();
				if (cpu.code.big) gen_call_function((void *)&DynRunException,"%Id%Id%F",save_info[sct].eip_change,save_info[sct].cycles);
				else gen_call_function((void *)&DynRunException,"%Iw%Id%F",save_info[sct].eip_change,save_info[sct].cycles);
				gen_return_fast(BR_Normal,true);
				break;
			case cycle_check:
				gen_return(BR_Cycles);
				break;
			case normal:
				dyn_loadstate(&save_info[sct].state);
				gen_dop_word_imm(DOP_ADD,decode.big_op,DREG(EIP),save_info[sct].eip_change);
				dyn_save_critical_regs();
				gen_return(BR_Cycles);
				break;
			case fpu_restore:
				dyn_loadstate(&save_info[sct].state);
				gen_load_host(&dyn_dh_fpu.state_used,DREG(TMPB),4);
				gen_sop_word(SOP_INC,true,DREG(TMPB));
				GenReg * gr1=FindDynReg(DREG(TMPB));
				cache_addb(0xdd);	// FRSTOR fpu.state (fpu_restore)
				cache_addb(0x25);
				cache_addd((Bit32u)(&(dyn_dh_fpu.state[0])));
				cache_addb(0x89);	// mov fpu.state_used,1
				cache_addb(0x05|(gr1->index<<3));
				cache_addd((Bit32u)(&(dyn_dh_fpu.state_used)));
				gen_releasereg(DREG(TMPB));
				dyn_synchstate(&save_info[sct].state);
				gen_create_jump(save_info[sct].return_pos);
				break;
		}
	}
	used_save_info=0;
}


#if !defined(X86_INLINED_MEMACCESS)
static void dyn_read_byte(DynReg * addr,DynReg * dst,Bitu high) {
	gen_protectflags();
	gen_call_function((void *)&mem_readb_checked_x86,"%Dd%Id",addr,&core_dyn.readdata);
	dyn_check_bool_exception_al();
	gen_mov_host(&core_dyn.readdata,dst,1,high);
}
static void dyn_write_byte(DynReg * addr,DynReg * val,Bitu high) {
	gen_protectflags();
	if (high) gen_call_function((void *)&mem_writeb_checked_x86,"%Dd%Dh",addr,val);
	else gen_call_function((void *)&mem_writeb_checked_x86,"%Dd%Dd",addr,val);
	dyn_check_bool_exception_al();
}
static void dyn_read_word(DynReg * addr,DynReg * dst,bool dword) {
	gen_protectflags();
	if (dword) gen_call_function((void *)&mem_readd_checked_x86,"%Dd%Id",addr,&core_dyn.readdata);
	else gen_call_function((void *)&mem_readw_checked_x86,"%Dd%Id",addr,&core_dyn.readdata);
	dyn_check_bool_exception_al();
	gen_mov_host(&core_dyn.readdata,dst,dword?4:2);
}
static void dyn_write_word(DynReg * addr,DynReg * val,bool dword) {
	gen_protectflags();
	if (dword) gen_call_function((void *)&mem_writed_checked_x86,"%Dd%Dd",addr,val);
	else gen_call_function((void *)&mem_writew_checked_x86,"%Dd%Dd",addr,val);
	dyn_check_bool_exception_al();
}
static void dyn_read_byte_release(DynReg * addr,DynReg * dst,Bitu high) {
	gen_protectflags();
	gen_call_function((void *)&mem_readb_checked_x86,"%Ddr%Id",addr,&core_dyn.readdata);
	dyn_check_bool_exception_al();
	gen_mov_host(&core_dyn.readdata,dst,1,high);
}
static void dyn_write_byte_release(DynReg * addr,DynReg * val,Bitu high) {
	gen_protectflags();
	if (high) gen_call_function((void *)&mem_writeb_checked_x86,"%Ddr%Dh",addr,val);
	else gen_call_function((void *)&mem_writeb_checked_x86,"%Ddr%Dd",addr,val);
	dyn_check_bool_exception_al();
}