Initial 64-bit recompiler.

Various 64-bit fixes.
Various fixes to allow building under MinGW-w64.

src/386_common.h

@@ -4,14 +4,14 @@ extern uint16_t ea_rseg;
 #undef writememb
 
 
-#define readmemb(s,a) ((readlookup2[((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF)?readmemb386l(s,a): *(uint8_t *)(readlookup2[((s)+(a))>>12] + (s) + (a)) )
+#define readmemb(s,a) ((readlookup2[(uint32_t)((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF)?readmemb386l(s,a): *(uint8_t *)(readlookup2[(uint32_t)((s)+(a))>>12] + (uint32_t)((s) + (a))) )
-#define readmemq(s,a) ((readlookup2[((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFF8)?readmemql(s,a):*(uint64_t *)(readlookup2[((s)+(a))>>12]+(s)+(a)))
+#define readmemq(s,a) ((readlookup2[(uint32_t)((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFF8)?readmemql(s,a):*(uint64_t *)(readlookup2[(uint32_t)((s)+(a))>>12]+(uint32_t)((s)+(a))))
 
-#define writememb(s,a,v) if (writelookup2[((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF) writememb386l(s,a,v); else *(uint8_t *)(writelookup2[((s) + (a)) >> 12] + (s) + (a)) = v
+#define writememb(s,a,v) if (writelookup2[(uint32_t)((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF) writememb386l(s,a,v); else *(uint8_t *)(writelookup2[(uint32_t)((s) + (a)) >> 12] + (uint32_t)((s) + (a))) = v
 
-#define writememw(s,a,v) if (writelookup2[((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFFE) writememwl(s,a,v); else *(uint16_t *)(writelookup2[((s) + (a)) >> 12] + (s) + (a)) = v
+#define writememw(s,a,v) if (writelookup2[(uint32_t)((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFFE) writememwl(s,a,v); else *(uint16_t *)(writelookup2[(uint32_t)((s) + (a)) >> 12] + (uint32_t)((s) + (a))) = v
-#define writememl(s,a,v) if (writelookup2[((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFFC) writememll(s,a,v); else *(uint32_t *)(writelookup2[((s) + (a)) >> 12] + (s) + (a)) = v
+#define writememl(s,a,v) if (writelookup2[(uint32_t)((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFFC) writememll(s,a,v); else *(uint32_t *)(writelookup2[(uint32_t)((s) + (a)) >> 12] + (uint32_t)((s) + (a))) = v
-#define writememq(s,a,v) if (writelookup2[((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFF8) writememql(s,a,v); else *(uint64_t *)(writelookup2[((s) + (a)) >> 12] + (s) + (a)) = v
+#define writememq(s,a,v) if (writelookup2[(uint32_t)((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFF8) writememql(s,a,v); else *(uint64_t *)(writelookup2[(uint32_t)((s) + (a)) >> 12] + (uint32_t)((s) + (a))) = v
 
 
 #define check_io_perm(port) if (!IOPLp || (eflags&VM_FLAG)) \

src/386_dynarec.c

@@ -135,10 +135,11 @@ static inline void fetch_ea_32_long(uint32_t rmdat)
         }
         if (easeg != 0xFFFFFFFF && ((easeg + eaaddr) & 0xFFF) <= 0xFFC)
         {
-                if ( readlookup2[(easeg + eaaddr) >> 12] != -1)
+                uint32_t addr = easeg + eaaddr;
-                   eal_r = (uint32_t *)(readlookup2[(easeg + eaaddr) >> 12] + easeg + eaaddr);
+                if ( readlookup2[addr >> 12] != -1)
-                if (writelookup2[(easeg + eaaddr) >> 12] != -1)
+                   eal_r = (uint32_t *)(readlookup2[addr >> 12] + addr);
-                   eal_w = (uint32_t *)(writelookup2[(easeg + eaaddr) >> 12] + easeg + eaaddr);
+                if (writelookup2[addr >> 12] != -1)
+                   eal_w = (uint32_t *)(writelookup2[addr >> 12] + addr);
         }
 }
 
@@ -176,10 +177,11 @@ static inline void fetch_ea_16_long(uint32_t rmdat)
         }
         if (easeg != 0xFFFFFFFF && ((easeg + eaaddr) & 0xFFF) <= 0xFFC)
         {
-                if ( readlookup2[(easeg + eaaddr) >> 12] != -1)
+                uint32_t addr = easeg + eaaddr;
-                   eal_r = (uint32_t *)(readlookup2[(easeg + eaaddr) >> 12] + easeg + eaaddr);
+                if ( readlookup2[addr >> 12] != -1)
-                if (writelookup2[(easeg + eaaddr) >> 12] != -1)
+                   eal_r = (uint32_t *)(readlookup2[addr >> 12] + addr);
-                   eal_w = (uint32_t *)(writelookup2[(easeg + eaaddr) >> 12] + easeg + eaaddr);
+                if (writelookup2[addr >> 12] != -1)
+                   eal_w = (uint32_t *)(writelookup2[addr >> 12] + addr);
         }
 }
 

src/386_dynarec_ops.c

@@ -18,6 +18,127 @@ extern uint32_t *mod1seg[8];
 
 /*Copy-and-pasted from 386_dynarec.c, is not in a header file because it will
   eventually be different for the dynarec ops*/
+#ifdef __amd64__
+static inline void fetch_ea_32_long(uint32_t rmdat)
+{
+        eal_r = eal_w = NULL;
+        easeg = ea_seg->base;
+        ea_rseg = ea_seg->seg;
+        if (rm == 4)
+        {
+                uint8_t sib = rmdat >> 8;
+                
+                switch (mod)
+                {
+                        case 0: 
+                        eaaddr = regs[sib & 7].l; 
+                        pc++; 
+                        break;
+                        case 1: 
+                        pc++;
+                        eaaddr = ((uint32_t)(int8_t)getbyte()) + regs[sib & 7].l; 
+//                        pc++; 
+                        break;
+                        case 2: 
+                        eaaddr = (fastreadl(cs + pc + 1)) + regs[sib & 7].l; 
+                        pc += 5; 
+                        break;
+                }
+                /*SIB byte present*/
+                if ((sib & 7) == 5 && !mod) 
+                        eaaddr = getlong();
+                else if ((sib & 6) == 4 && !ssegs)
+                {
+                        easeg = ss;
+                        ea_rseg = SS;
+                        ea_seg = &_ss;
+                }
+                if (((sib >> 3) & 7) != 4) 
+                        eaaddr += regs[(sib >> 3) & 7].l << (sib >> 6);
+        }
+        else
+        {
+                eaaddr = regs[rm].l;
+                if (mod) 
+                {
+                        if (rm == 5 && !ssegs)
+                        {
+                                easeg = ss;
+                                ea_rseg = SS;
+                                ea_seg = &_ss;
+                        }
+                        if (mod == 1) 
+                        { 
+                                eaaddr += ((uint32_t)(int8_t)(rmdat >> 8)); 
+                                pc++; 
+                        }
+                        else          
+                        {
+                                eaaddr += getlong(); 
+                        }
+                }
+                else if (rm == 5) 
+                {
+                        eaaddr = getlong();
+                }
+        }
+        if (easeg != 0xFFFFFFFF && ((easeg + eaaddr) & 0xFFF) <= 0xFFC)
+        {
+                uint32_t addr = easeg + eaaddr;
+                if ( readlookup2[addr >> 12] != -1)
+                   eal_r = (uint32_t *)(readlookup2[addr >> 12] + addr);
+                if (writelookup2[addr >> 12] != -1)
+                   eal_w = (uint32_t *)(writelookup2[addr >> 12] + addr);
+        }
+}
+
+static inline void fetch_ea_16_long(uint32_t rmdat)
+{
+        eal_r = eal_w = NULL;
+        easeg = ea_seg->base;
+        ea_rseg = ea_seg->seg;
+        if (!mod && rm == 6) 
+        { 
+                eaaddr = getword();
+        }
+        else
+        {
+                switch (mod)
+                {
+                        case 0:
+                        eaaddr = 0;
+                        break;
+                        case 1:
+                        eaaddr = (uint16_t)(int8_t)(rmdat >> 8); pc++;
+                        break;
+                        case 2:
+                        eaaddr = getword();
+                        break;
+                }
+                eaaddr += (*mod1add[0][rm]) + (*mod1add[1][rm]);
+                if (mod1seg[rm] == &ss && !ssegs)
+                {
+                        easeg = ss;
+                        ea_rseg = SS;
+                        ea_seg = &_ss;
+                }
+                eaaddr &= 0xFFFF;
+        }
+        if (easeg != 0xFFFFFFFF && ((easeg + eaaddr) & 0xFFF) <= 0xFFC)
+        {
+                uint32_t addr = easeg + eaaddr;
+                if ( readlookup2[addr >> 12] != -1)
+                   eal_r = (uint32_t *)(readlookup2[addr >> 12] + addr);
+                if (writelookup2[addr >> 12] != -1)
+                   eal_w = (uint32_t *)(writelookup2[addr >> 12] + addr);
+        }
+}
+
+#define fetch_ea_16(rmdat)              pc++; mod=(rmdat >> 6) & 3; reg=(rmdat >> 3) & 7; rm = rmdat & 7; if (mod != 3) { fetch_ea_16_long(rmdat); if (abrt) return 1; } 
+#define fetch_ea_32(rmdat)              pc++; mod=(rmdat >> 6) & 3; reg=(rmdat >> 3) & 7; rm = rmdat & 7; if (mod != 3) { fetch_ea_32_long(rmdat); } if (abrt) return 1
+
+#else /*__amd64__*/
+
 static inline void fetch_ea_32_long(uint32_t rmdat)
 {
         eal_r = eal_w = NULL;
@@ -49,6 +170,10 @@ static inline void fetch_ea_16_long(uint32_t rmdat)
 #define fetch_ea_16(rmdat)              pc++; if (mod != 3) fetch_ea_16_long(rmdat); 
 #define fetch_ea_32(rmdat)              pc++; if (mod != 3) fetch_ea_32_long(rmdat); 
 
+#endif /*__amd64__*/
+
+
+
 #define OP_TABLE(name) dynarec_ops_ ## name
 #define CLOCK_CYCLES(c) 
 #define CLOCK_CYCLES_ALWAYS(c) cycles -= (c)

src/808x.c

@@ -594,7 +594,7 @@ chdir(pcempath);
         printf("ES : base=%06X limit=%08X access=%02X  limit_low=%08X limit_high=%08X\n",es,_es.limit,_es.access, _es.limit_low, _es.limit_high);
         if (is386)
         {
-                printf("FS : base=%06X limit=%08X access=%02X  limit_low=%08X limit_high=%08X\n",fs,_fs.limit,_fs.access, _fs.limit_low, _fs.limit_high);
+                printf("FS : base=%06X limit=%08X access=%02X  limit_low=%08X limit_high=%08X\n",seg_fs,_fs.limit,_fs.access, _fs.limit_low, _fs.limit_high);
                 printf("GS : base=%06X limit=%08X access=%02X  limit_low=%08X limit_high=%08X\n",gs,_gs.limit,_gs.access, _gs.limit_low, _gs.limit_high);
         }
         printf("SS : base=%06X limit=%08X access=%02X  limit_low=%08X limit_high=%08X\n",ss,_ss.limit,_ss.access, _ss.limit_low, _ss.limit_high);

src/Makefile.mingw64

@@ -0,0 +1,47 @@
+VPATH = . dosbox resid-fp
+CPP  = g++.exe
+CC   = gcc.exe
+WINDRES = windres.exe
+CFLAGS = -O3 -fomit-frame-pointer
+OBJ = 386.o 386_dynarec.o 386_dynarec_ops.o 808x.o acer386sx.o ali1429.o amstrad.o cdrom-ioctl.o \
+	codegen.o codegen_ops.o codegen_timing_486.o codegen_timing_pentium.o codegen_x86-64.o compaq.o config.o cpu.o dac.o \
+	device.o disc.o disc_fdi.o disc_img.o dma.o fdc.o fdc37c665.o fdi2raw.o gameport.o headland.o i430lx.o i430fx.o \
+	i430vx.o ide.o intel.o intel_flash.o io.o jim.o keyboard.o keyboard_amstrad.o keyboard_at.o \
+	keyboard_olim24.o keyboard_pcjr.o keyboard_xt.o lpt.o mcr.o mem.o model.o mouse.o mouse_ps2.o \
+	mouse_serial.o neat.o nmi.o nvr.o olivetti_m24.o opti.o pc.o pci.o pic.o piix.o pit.o ppi.o ps1.o rom.o \
+	serial.o sis496.o sound.o sound_ad1848.o sound_adlib.o sound_adlibgold.o sound_cms.o sound_dbopl.o \
+	sound_emu8k.o sound_gus.o sound_mpu401_uart.o sound_opl.o sound_pas16.o sound_resid.o \
+	sound_sb.o sound_sb_dsp.o sound_sn76489.o sound_speaker.o sound_ssi2001.o sound_wss.o \
+	soundopenal.o timer.o um8881f.o um8669f.o vid_ati_eeprom.o vid_ati_mach64.o vid_ati18800.o \
+	vid_ati28800.o vid_ati68860_ramdac.o vid_cga.o vid_cl5429.o vid_ega.o vid_et4000.o \
+	vid_et4000w32.o vid_et4000w32i.o vid_hercules.o vid_icd2061.o vid_ics2595.o vid_mda.o \
+	vid_olivetti_m24.o vid_oti067.o vid_paradise.o vid_pc1512.o vid_pc1640.o vid_pc200.o \
+	vid_pcjr.o vid_s3.o vid_s3_virge.o vid_sdac_ramdac.o vid_stg_ramdac.o vid_svga.o \
+	vid_svga_render.o vid_tandy.o vid_tgui9440.o vid_tkd8001_ramdac.o vid_tvga.o vid_unk_ramdac.o \
+	vid_vga.o vid_voodoo.o video.o wd76c10.o win.o win-config.o win-d3d.o win-d3d-fs.o win-ddraw.o \
+	win-ddraw-fs.o win-deviceconfig.o win-hdconf.o win-joystick.o win-keyboard.o win-midi.o win-mouse.o \
+	win-status.o win-time.o win-video.o x86seg.o x87.o xtide.o pc.res
+FMOBJ = dbopl.o
+SIDOBJ = convolve.o convolve-sse.o envelope.o extfilt.o filter.o pot.o sid.o voice.o wave6581__ST.o wave6581_P_T.o wave6581_PS_.o wave6581_PST.o wave8580__ST.o wave8580_P_T.o wave8580_PS_.o wave8580_PST.o wave.o
+
+
+LIBS = -mwindows -lwinmm -lopenal32 -lddraw -ldinput -ldxguid -ld3d9 -lstdc++
+
+PCem64.exe: $(OBJ) $(FMOBJ) $(SIDOBJ)
+	$(CC) $(OBJ) $(FMOBJ) $(SIDOBJ) -o "PCem64.exe" $(LIBS)
+
+all : PCem64.exe
+
+clean :
+	rm *.o
+	rm *.exe
+	rm *.res
+
+%.o : %.c
+	$(CC) $(CFLAGS) -c $<
+
+%.o : %.cc
+	$(CPP) $(CFLAGS) -c $<
+
+pc.res: pc.rc
+	$(WINDRES) -i pc.rc --input-format=rc -o pc.res -O coff 

src/cdrom-ioctl.c

@@ -2,20 +2,26 @@
 
 #include <windows.h>
 #include <io.h>
+#ifdef __MINGW64__
+#include "ntddcdrm.h"
+#else
 #include "ddk/ntddcdrm.h"
-//#include "ntddcdrm.h"
+#endif
 #include "ibm.h"
 #include "ide.h"
 #include "cdrom-ioctl.h"
 
 int cdrom_drive;
 
+#ifndef __MINGW64__
 typedef struct _CDROM_TOC_SESSION_DATA {
   UCHAR      Length[2];
   UCHAR      FirstCompleteSession;
   UCHAR      LastCompleteSession;
   TRACK_DATA TrackData[1];
 } CDROM_TOC_SESSION_DATA, *PCDROM_TOC_SESSION_DATA;
+#endif
+
 static ATAPI ioctl_atapi;
 
 static uint32_t last_block = 0;

src/codegen.h

@@ -138,6 +138,16 @@ static inline void addlong(uint32_t val)
         }
 }
 
+static inline void addquad(uint64_t val)
+{
+        *(uint64_t *)&codeblock[block_current].data[block_pos] = val;
+        block_pos += 8;
+        if (block_pos >= 1760)
+        {
+                CPU_BLOCK_END();
+        }
+}
+
 /*Current physical page of block being recompiled. -1 if no recompilation taking place */
 extern uint32_t recomp_page;
 

src/codegen_x86-64.h

@@ -0,0 +1,19 @@
+#define BLOCK_SIZE 0x4000
+#define BLOCK_MASK 0x3fff
+#define BLOCK_START 0
+
+#define HASH_SIZE 0x20000
+#define HASH_MASK 0x1ffff
+
+#define HASH(l) ((l) & 0x1ffff)
+
+#define BLOCK_EXIT_OFFSET 0x7f0
+#define BLOCK_GPF_OFFSET (BLOCK_EXIT_OFFSET - 20)
+
+enum
+{
+        OP_RET = 0xc3
+};
+
+#define NR_HOST_REGS 3
+extern int host_reg_mapping[NR_HOST_REGS];

src/ibm.h

@@ -18,8 +18,8 @@ int writelnext;
 extern int mmu_perm;
 
 #define readmemb(a) ((readlookup2[(a)>>12]==-1)?readmembl(a):*(uint8_t *)(readlookup2[(a) >> 12] + (a)))
-#define readmemw(s,a) ((readlookup2[((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFFE)?readmemwl(s,a):*(uint16_t *)(readlookup2[((s)+(a))>>12]+(s)+(a)))
+#define readmemw(s,a) ((readlookup2[(uint32_t)((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFFE)?readmemwl(s,a):*(uint16_t *)(readlookup2[(uint32_t)((s)+(a))>>12]+(uint32_t)((s)+(a))))
-#define readmeml(s,a) ((readlookup2[((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFFC)?readmemll(s,a):*(uint32_t *)(readlookup2[((s)+(a))>>12]+(s)+(a)))
+#define readmeml(s,a) ((readlookup2[(uint32_t)((s)+(a))>>12]==-1 || (s)==0xFFFFFFFF || (((s)+(a))&0xFFF)>0xFFC)?readmemll(s,a):*(uint32_t *)(readlookup2[(uint32_t)((s)+(a))>>12]+(uint32_t)((s)+(a))))
 
 //#define writememb(a,v) if (writelookup2[(a)>>12]==0xFFFFFFFF) writemembl(a,v); else ram[writelookup2[(a)>>12]+((a)&0xFFF)]=v
 //#define writememw(s,a,v) if (writelookup2[((s)+(a))>>12]==0xFFFFFFFF || (s)==0xFFFFFFFF) writememwl(s,a,v); else *((uint16_t *)(&ram[writelookup2[((s)+(a))>>12]+(((s)+(a))&0xFFF)]))=v
@@ -142,7 +142,7 @@ uint8_t *pccache2;
 #define ds _ds.base
 #define es _es.base
 #define ss _ss.base
-#define fs _fs.base
+#define seg_fs _fs.base
 #define gs _gs.base
 
 #define CPL ((_cs.access>>5)&3)

src/pc.rc

@@ -1,6 +1,10 @@
 #include <windows.h>
 #include "resources.h"
 
+#ifndef UPDOWN_CLASS
+#define UPDOWN_CLASS L"msctls_updown32"
+#endif
+
 MainMenu MENU DISCARDABLE
 BEGIN
         POPUP "&File"

src/resid-fp/convolve-sse.cc

@@ -32,7 +32,7 @@ float convolve_sse(const float *a, const float *b, int n)
     int diff = (int) (a - b) & 0xf;
     /* long cast is no-op for x86-32, but x86-64 gcc needs 64 bit intermediate
      * to convince compiler we mean this. */
-    unsigned int a_align = (unsigned int) (unsigned long) a & 0xf;
+    unsigned int a_align = (unsigned int) (uintptr_t) a & 0xf;
 
     /* advance if necessary. We can't let n fall < 0, so no while (n --). */
     while (n > 0 && a_align != 0 && a_align != 16) {

src/soundopenal.c

@@ -4,8 +4,12 @@
 #include <stdlib.h>
 #ifdef USE_OPENAL
 #include <AL/al.h>
+#ifdef __MINGW64__
+#include <AL/alc.h>
+#else
 #include <AL/alut.h>
 #endif
+#endif
 #include "ibm.h"
 
 FILE *allog;
@@ -18,7 +22,40 @@ ALenum format;     // internal format
 #define BUFLEN SOUNDBUFLEN
 
 void closeal();
+#ifdef __MINGW64__
+ALvoid  alutInit(ALint *argc,ALbyte **argv) 
+{
+	ALCcontext *Context;
+	ALCdevice *Device;
+	
+	//Open device
+ 	Device=alcOpenDevice((ALubyte*)"DirectSound3D");
+	//Create context(s)
+	Context=alcCreateContext(Device,NULL);
+	//Set active context
+	alcMakeContextCurrent(Context);
+	//Register extensions
+}
 
+ALvoid  alutExit(ALvoid) 
+{
+	ALCcontext *Context;
+	ALCdevice *Device;
+
+	//Unregister extensions
+
+	//Get active context
+	Context=alcGetCurrentContext();
+	//Get device for active context
+	Device=alcGetContextsDevice(Context);
+	//Disable context
+	alcMakeContextCurrent(NULL);
+	//Release context(s)
+	alcDestroyContext(Context);
+	//Close device
+	alcCloseDevice(Device);
+}
+#endif
 void initalmain(int argc, char *argv[])
 {
 #ifdef USE_OPENAL

src/x86.h

@@ -50,7 +50,7 @@ int optype;
 #define JMP 1
 #define CALL 2
 #define IRET 3
-#define INT 4
+#define OPTYPE_INT 4
 
 uint32_t oxpc;
 

src/x86seg.c

@@ -1934,7 +1934,7 @@ void pmodeint(int num, int soft)
                                         x86np("Int task gate not present\n", segdat[1] & 0xfffc);
                                         return;
                                 }
-                optype=INT;
+                optype=OPTYPE_INT;
                 cpl_override=1;
                 taskswitch286(seg,segdat2,segdat2[2]&0x800);
                 cpl_override=0;
@@ -2366,7 +2366,7 @@ void taskswitch286(uint16_t seg, uint16_t *segdat, int is32)
                 new_ldt=readmemw(base,0x60);
                 
                 if (abrt) return;
-                if (optype==JMP || optype==INT)
+                if (optype==JMP || optype==OPTYPE_INT)
                 {
                         if (tr.seg&4) tempw=readmemw(ldt.base,(tr.seg&~7)+4);
                         else          tempw=readmemw(gdt.base,(tr.seg&~7)+4);
@@ -2402,13 +2402,13 @@ void taskswitch286(uint16_t seg, uint16_t *segdat, int is32)
                 writememl(tr.base,0x5C,GS);
                 writememl(tr.base,0x60,ldt.seg);
                 
-                if (optype==INT)
+                if (optype==OPTYPE_INT)
                 {
                         writememl(base,0,tr.seg);
                         new_flags|=NT_FLAG;
                 }
                 if (abrt) return;
-                if (optype==JMP || optype==INT)
+                if (optype==JMP || optype==OPTYPE_INT)
                 {
                         if (tr.seg&4) tempw=readmemw(ldt.base,(seg&~7)+4);
                         else          tempw=readmemw(gdt.base,(seg&~7)+4);