ea_lookup.h

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

{
	EAPoint seg_base;
	Bit16u off;
	switch ((inst.rm_mod<<3)|inst.rm_eai) {
	case 0x00:
		off=reg_bx+reg_si;
		seg_base=SegBase(ds);
		break;
	case 0x01:
		off=reg_bx+reg_di;
		seg_base=SegBase(ds);
		break;
	case 0x02:
		off=reg_bp+reg_si;
		seg_base=SegBase(ss);
		break;
	case 0x03:
		off=reg_bp+reg_di;
		seg_base=SegBase(ss);
		break;
	case 0x04:
		off=reg_si;
		seg_base=SegBase(ds);
		break;
	case 0x05:
		off=reg_di;
		seg_base=SegBase(ds);
		break;
	case 0x06:
		off=Fetchw();
		seg_base=SegBase(ds);
		break;
	case 0x07:
		off=reg_bx;
		seg_base=SegBase(ds);
		break;

	case 0x08:
		off=reg_bx+reg_si+Fetchbs();
		seg_base=SegBase(ds);
		break;
	case 0x09:
		off=reg_bx+reg_di+Fetchbs();
		seg_base=SegBase(ds);
		break;
	case 0x0a:
		off=reg_bp+reg_si+Fetchbs();
		seg_base=SegBase(ss);
		break;
	case 0x0b:
		off=reg_bp+reg_di+Fetchbs();
		seg_base=SegBase(ss);
		break;
	case 0x0c:
		off=reg_si+Fetchbs();
		seg_base=SegBase(ds);
		break;
	case 0x0d:
		off=reg_di+Fetchbs();
		seg_base=SegBase(ds);
		break;
	case 0x0e:
		off=reg_bp+Fetchbs();
		seg_base=SegBase(ss);
		break;
	case 0x0f:
		off=reg_bx+Fetchbs();
		seg_base=SegBase(ds);
		break;
	
	case 0x10:
		off=reg_bx+reg_si+Fetchws();
		seg_base=SegBase(ds);
		break;
	case 0x11:
		off=reg_bx+reg_di+Fetchws();
		seg_base=SegBase(ds);
		break;
	case 0x12:
		off=reg_bp+reg_si+Fetchws();
		seg_base=SegBase(ss);
		break;
	case 0x13:
		off=reg_bp+reg_di+Fetchws();
		seg_base=SegBase(ss);
		break;
	case 0x14:
		off=reg_si+Fetchws();
		seg_base=SegBase(ds);
		break;
	case 0x15:
		off=reg_di+Fetchws();
		seg_base=SegBase(ds);
		break;
	case 0x16:
		off=reg_bp+Fetchws();
		seg_base=SegBase(ss);
		break;
	case 0x17:
		off=reg_bx+Fetchws();
		seg_base=SegBase(ds);
		break;
	}
	inst.rm_off=off;
	if (inst.prefix & PREFIX_SEG) {
		inst.rm_eaa=inst.seg.base+off;
	} else {
		inst.rm_eaa=seg_base+off;
	}
} else  {


#define SIB(MODE)	{												\
	Bitu sib=Fetchb();												\
	switch (sib&7) {												\
	case 0:seg_base=SegBase(ds);off=reg_eax;break;					\
	case 1:seg_base=SegBase(ds);off=reg_ecx;break;					\
	case 2:seg_base=SegBase(ds);off=reg_edx;break;					\
	case 3:seg_base=SegBase(ds);off=reg_ebx;break;					\
	case 4:seg_base=SegBase(ss);off=reg_esp;break;					\
	case 5:if (!MODE) {	seg_base=SegBase(ds);off=Fetchd();break;	\
		   } else { seg_base=SegBase(ss);off=reg_ebp;break;}		\
	case 6:seg_base=SegBase(ds);off=reg_esi;break;					\
	case 7:seg_base=SegBase(ds);off=reg_edi;break;					\
	}																\
	off+=*SIBIndex[(sib >> 3) &7] << (sib >> 6);					\
};																	
	static Bit32u SIBZero=0;
	static Bit32u * SIBIndex[8]= { &reg_eax,&reg_ecx,&reg_edx,&reg_ebx,&SIBZero,&reg_ebp,&reg_esi,&reg_edi };
	EAPoint seg_base;
	Bit32u off;
	switch ((inst.rm_mod<<3)|inst.rm_eai) {
	case 0x00:
		off=reg_eax;
		seg_base=SegBase(ds);
		break;
	case 0x01:
		off=reg_ecx;
		seg_base=SegBase(ds);
		break;
	case 0x02:
		off=reg_edx;
		seg_base=SegBase(ds);
		break;
	case 0x03:
		off=reg_ebx;
		seg_base=SegBase(ds);
		break;
	case 0x04:
		SIB(0);
		break;
	case 0x05:
		off=Fetchd();
		seg_base=SegBase(ds);
		break;
	case 0x06:
		off=reg_esi;
		seg_base=SegBase(ds);
		break;
	case 0x07:
		off=reg_edi;
		seg_base=SegBase(ds);
		break;
	
	case 0x08:
		off=reg_eax+Fetchbs();
		seg_base=SegBase(ds);
		break;
	case 0x09:
		off=reg_ecx+Fetchbs();
		seg_base=SegBase(ds);
		break;
	case 0x0a:
		off=reg_edx+Fetchbs();
		seg_base=SegBase(ds);
		break;
	case 0x0b:
		off=reg_ebx+Fetchbs();
		seg_base=SegBase(ds);
		break;
	case 0x0c:
		SIB(1);
		off+=Fetchbs();
		break;
	case 0x0d:
		off=reg_ebp+Fetchbs();
		seg_base=SegBase(ss);
		break;
	case 0x0e:
		off=reg_esi+Fetchbs();
		seg_base=SegBase(ds);
		break;
	case 0x0f:
		off=reg_edi+Fetchbs();
		seg_base=SegBase(ds);
		break;

	case 0x10:
		off=reg_eax+Fetchds();
		seg_base=SegBase(ds);
		break;
	case 0x11:
		off=reg_ecx+Fetchds();
		seg_base=SegBase(ds);
		break;
	case 0x12:
		off=reg_edx+Fetchds();
		seg_base=SegBase(ds);
		break;
	case 0x13:
		off=reg_ebx+Fetchds();
		seg_base=SegBase(ds);
		break;
	case 0x14:
		SIB(1);
		off+=Fetchds();
		break;
	case 0x15:
		off=reg_ebp+Fetchds();
		seg_base=SegBase(ss);
		break;
	case 0x16:
		off=reg_esi+Fetchds();
		seg_base=SegBase(ds);
		break;
	case 0x17:
		off=reg_edi+Fetchds();
		seg_base=SegBase(ds);
		break;
	}
	inst.rm_off=off;
	if (inst.prefix & PREFIX_SEG) {
		inst.rm_eaa=inst.seg.base+off;
	} else {
		inst.rm_eaa=seg_base+off;
	}
}