use new timer API

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@689 c046a42c-6fe2-441c-8c8c-71466251a162

hw/i8254.c

@@ -43,6 +43,8 @@
 #include "cpu.h"
 #include "vl.h"
 
+//#define DEBUG_PIT
+
 #define RW_STATE_LSB 0
 #define RW_STATE_MSB 1
 #define RW_STATE_WORD0 2
@@ -52,12 +54,14 @@
 
 PITChannelState pit_channels[3];
 
+static void pit_irq_timer_update(PITChannelState *s, int64_t current_time);
+
 static int pit_get_count(PITChannelState *s)
 {
     uint64_t d;
     int counter;
 
-    d = muldiv64(cpu_get_ticks() - s->count_load_time, PIT_FREQ, ticks_per_sec);
+    d = muldiv64(qemu_get_clock(vm_clock) - s->count_load_time, PIT_FREQ, ticks_per_sec);
     switch(s->mode) {
     case 0:
     case 1:
@@ -77,12 +81,12 @@ static int pit_get_count(PITChannelState *s)
 }
 
 /* get pit output bit */
-int pit_get_out(PITChannelState *s)
+int pit_get_out(PITChannelState *s, int64_t current_time)
 {
     uint64_t d;
     int out;
 
-    d = muldiv64(cpu_get_ticks() - s->count_load_time, PIT_FREQ, ticks_per_sec);
+    d = muldiv64(current_time - s->count_load_time, PIT_FREQ, ticks_per_sec);
     switch(s->mode) {
     default:
     case 0:
@@ -108,53 +112,51 @@ int pit_get_out(PITChannelState *s)
     return out;
 }
 
-/* get the number of 0 to 1 transitions we had since we call this
-   function */
-/* XXX: maybe better to use ticks precision to avoid getting edges
-   twice if checks are done at very small intervals */
-int pit_get_out_edges(PITChannelState *s)
+/* return -1 if no transition will occur.  */
+static int64_t pit_get_next_transition_time(PITChannelState *s, 
+                                            int64_t current_time)
 {
-    uint64_t d1, d2;
-    int64_t ticks;
-    int ret, v;
+    uint64_t d, next_time, base;
+    int period2;
 
-    ticks = cpu_get_ticks();
-    d1 = muldiv64(s->count_last_edge_check_time - s->count_load_time, 
-                 PIT_FREQ, ticks_per_sec);
-    d2 = muldiv64(ticks - s->count_load_time, 
-                  PIT_FREQ, ticks_per_sec);
-    s->count_last_edge_check_time = ticks;
+    d = muldiv64(current_time - s->count_load_time, PIT_FREQ, ticks_per_sec);
     switch(s->mode) {
     default:
     case 0:
-        if (d1 < s->count && d2 >= s->count)
-            ret = 1;
-        else
-            ret = 0;
-        break;
     case 1:
-        ret = 0;
+        if (d < s->count)
+            next_time = s->count;
+        else
+            return -1;
         break;
     case 2:
-        d1 /= s->count;
-        d2 /= s->count;
-        ret = d2 - d1;
+        base = (d / s->count) * s->count;
+        if ((d - base) == 0 && d != 0)
+            next_time = base + s->count;
+        else
+            next_time = base + s->count + 1;
         break;
     case 3:
-        v = s->count - ((s->count + 1) >> 1);
-        d1 = (d1 + v) / s->count;
-        d2 = (d2 + v) / s->count;
-        ret = d2 - d1;
+        base = (d / s->count) * s->count;
+        period2 = ((s->count + 1) >> 1);
+        if ((d - base) < period2) 
+            next_time = base + period2;
+        else
+            next_time = base + s->count;
         break;
     case 4:
     case 5:
-        if (d1 < s->count && d2 >= s->count)
-            ret = 1;
+        if (d < s->count)
+            next_time = s->count;
+        else if (d == s->count)
+            next_time = s->count + 1;
         else
-            ret = 0;
+            return -1;
         break;
     }
-    return ret;
+    /* convert to timer units */
+    next_time = s->count_load_time + muldiv64(next_time, ticks_per_sec, PIT_FREQ);
+    return next_time;
 }
 
 /* val must be 0 or 1 */
@@ -170,16 +172,16 @@ void pit_set_gate(PITChannelState *s, int val)
     case 5:
         if (s->gate < val) {
             /* restart counting on rising edge */
-            s->count_load_time = cpu_get_ticks();
-            s->count_last_edge_check_time = s->count_load_time;
+            s->count_load_time = qemu_get_clock(vm_clock);
+            pit_irq_timer_update(s, s->count_load_time);
         }
         break;
     case 2:
     case 3:
         if (s->gate < val) {
             /* restart counting on rising edge */
-            s->count_load_time = cpu_get_ticks();
-            s->count_last_edge_check_time = s->count_load_time;
+            s->count_load_time = qemu_get_clock(vm_clock);
+            pit_irq_timer_update(s, s->count_load_time);
         }
         /* XXX: disable/enable counting */
         break;
@@ -191,14 +193,9 @@ static inline void pit_load_count(PITChannelState *s, int val)
 {
     if (val == 0)
         val = 0x10000;
-    s->count_load_time = cpu_get_ticks();
-    s->count_last_edge_check_time = s->count_load_time;
+    s->count_load_time = qemu_get_clock(vm_clock);
     s->count = val;
-    if (s == &pit_channels[0] && val <= pit_min_timer_count) {
-        fprintf(stderr, 
-                "\nWARNING: qemu: on your system, accurate timer emulation is impossible if its frequency is more than %d Hz. If using a 2.6 guest Linux kernel, you must patch asm/param.h to change HZ from 1000 to 100.\n\n", 
-                PIT_FREQ / pit_min_timer_count);
-    }
+    pit_irq_timer_update(s, s->count_load_time);
 }
 
 static void pit_ioport_write(void *opaque, uint32_t addr, uint32_t val)
@@ -222,6 +219,7 @@ static void pit_ioport_write(void *opaque, uint32_t addr, uint32_t val)
             s->mode = (val >> 1) & 7;
             s->bcd = val & 1;
             s->rw_state = access - 1 +  RW_STATE_LSB;
+            /* XXX: update irq timer ? */
             break;
         }
     } else {
@@ -279,18 +277,100 @@ static uint32_t pit_ioport_read(void *opaque, uint32_t addr)
     return ret;
 }
 
-void pit_init(int base)
+static void pit_irq_timer_update(PITChannelState *s, int64_t current_time)
+{
+    int64_t expire_time;
+    int irq_level;
+
+    if (!s->irq_timer)
+        return;
+    expire_time = pit_get_next_transition_time(s, current_time);
+    irq_level = pit_get_out(s, current_time);
+    pic_set_irq(s->irq, irq_level);
+#ifdef DEBUG_PIT
+    printf("irq_level=%d next_delay=%f\n",
+           irq_level, 
+           (double)(expire_time - current_time) / ticks_per_sec);
+#endif
+    s->next_transition_time = expire_time;
+    if (expire_time != -1)
+        qemu_mod_timer(s->irq_timer, expire_time);
+    else
+        qemu_del_timer(s->irq_timer);
+}
+
+static void pit_irq_timer(void *opaque)
+{
+    PITChannelState *s = opaque;
+
+    pit_irq_timer_update(s, s->next_transition_time);
+}
+
+static void pit_save(QEMUFile *f, void *opaque)
+{
+    PITChannelState *s;
+    int i;
+    
+    for(i = 0; i < 3; i++) {
+        s = &pit_channels[i];
+        qemu_put_be32s(f, &s->count);
+        qemu_put_be16s(f, &s->latched_count);
+        qemu_put_8s(f, &s->rw_state);
+        qemu_put_8s(f, &s->mode);
+        qemu_put_8s(f, &s->bcd);
+        qemu_put_8s(f, &s->gate);
+        qemu_put_be64s(f, &s->count_load_time);
+        if (s->irq_timer) {
+            qemu_put_be64s(f, &s->next_transition_time);
+            qemu_put_timer(f, s->irq_timer);
+        }
+    }
+}
+
+static int pit_load(QEMUFile *f, void *opaque, int version_id)
+{
+    PITChannelState *s;
+    int i;
+    
+    if (version_id != 1)
+        return -EINVAL;
+
+    for(i = 0; i < 3; i++) {
+        s = &pit_channels[i];
+        qemu_get_be32s(f, &s->count);
+        qemu_get_be16s(f, &s->latched_count);
+        qemu_get_8s(f, &s->rw_state);
+        qemu_get_8s(f, &s->mode);
+        qemu_get_8s(f, &s->bcd);
+        qemu_get_8s(f, &s->gate);
+        qemu_get_be64s(f, &s->count_load_time);
+        if (s->irq_timer) {
+            qemu_get_be64s(f, &s->next_transition_time);
+            qemu_get_timer(f, s->irq_timer);
+        }
+    }
+    return 0;
+}
+
+void pit_init(int base, int irq)
 {
     PITChannelState *s;
     int i;
 
     for(i = 0;i < 3; i++) {
         s = &pit_channels[i];
+        if (i == 0) {
+            /* the timer 0 is connected to an IRQ */
+            s->irq_timer = qemu_new_timer(vm_clock, pit_irq_timer, s);
+            s->irq = irq;
+        }
         s->mode = 3;
         s->gate = (i != 2);
         pit_load_count(s, 0);
     }
 
+    register_savevm("i8254", base, 1, pit_save, pit_load, NULL);
+
     register_ioport_write(base, 4, 1, pit_ioport_write, NULL);
     register_ioport_read(base, 3, 1, pit_ioport_read, NULL);
 }

hw/i8259.c

@@ -122,7 +122,7 @@ static int pic_get_irq(PicState *s)
 
 /* raise irq to CPU if necessary. must be called every time the active
    irq may change */
-void pic_update_irq(void)
+static void pic_update_irq(void)
 {
     int irq2, irq;
 
@@ -160,7 +160,6 @@ void pic_update_irq(void)
 
 #ifdef DEBUG_IRQ_LATENCY
 int64_t irq_time[16];
-int64_t cpu_get_ticks(void);
 #endif
 #if defined(DEBUG_PIC)
 int irq_level[16];
@@ -376,11 +375,62 @@ uint32_t pic_intack_read(CPUState *env)
     return ret;
 }
 
+static void pic_save(QEMUFile *f, void *opaque)
+{
+    PicState *s = opaque;
+    
+    qemu_put_8s(f, &s->last_irr);
+    qemu_put_8s(f, &s->irr);
+    qemu_put_8s(f, &s->imr);
+    qemu_put_8s(f, &s->isr);
+    qemu_put_8s(f, &s->priority_add);
+    qemu_put_8s(f, &s->irq_base);
+    qemu_put_8s(f, &s->read_reg_select);
+    qemu_put_8s(f, &s->poll);
+    qemu_put_8s(f, &s->special_mask);
+    qemu_put_8s(f, &s->init_state);
+    qemu_put_8s(f, &s->auto_eoi);
+    qemu_put_8s(f, &s->rotate_on_auto_eoi);
+    qemu_put_8s(f, &s->special_fully_nested_mode);
+    qemu_put_8s(f, &s->init4);
+}
+
+static int pic_load(QEMUFile *f, void *opaque, int version_id)
+{
+    PicState *s = opaque;
+    
+    if (version_id != 1)
+        return -EINVAL;
+
+    qemu_get_8s(f, &s->last_irr);
+    qemu_get_8s(f, &s->irr);
+    qemu_get_8s(f, &s->imr);
+    qemu_get_8s(f, &s->isr);
+    qemu_get_8s(f, &s->priority_add);
+    qemu_get_8s(f, &s->irq_base);
+    qemu_get_8s(f, &s->read_reg_select);
+    qemu_get_8s(f, &s->poll);
+    qemu_get_8s(f, &s->special_mask);
+    qemu_get_8s(f, &s->init_state);
+    qemu_get_8s(f, &s->auto_eoi);
+    qemu_get_8s(f, &s->rotate_on_auto_eoi);
+    qemu_get_8s(f, &s->special_fully_nested_mode);
+    qemu_get_8s(f, &s->init4);
+    return 0;
+}
+
+/* XXX: add generic master/slave system */
+static void pic_init1(int io_addr, PicState *s)
+{
+    register_ioport_write(io_addr, 2, 1, pic_ioport_write, s);
+    register_ioport_read(io_addr, 2, 1, pic_ioport_read, s);
+
+    register_savevm("i8259", io_addr, 1, pic_save, pic_load, s);
+}
+
 void pic_init(void)
 {
-    register_ioport_write(0x20, 2, 1, pic_ioport_write, &pics[0]);
-    register_ioport_read(0x20, 2, 1, pic_ioport_read, &pics[0]);
-    register_ioport_write(0xa0, 2, 1, pic_ioport_write, &pics[1]);
-    register_ioport_read(0xa0, 2, 1, pic_ioport_read, &pics[1]);
+    pic_init1(0x20, &pics[0]);
+    pic_init1(0xa0, &pics[1]);
 }
 

hw/ne2000.c

@@ -471,5 +471,5 @@ void ne2000_init(int base, int irq, NetDriverState *nd)
 
     ne2000_reset(s);
 
-    add_fd_read_handler(nd->fd, ne2000_can_receive, ne2000_receive, s);
+    qemu_add_fd_read_handler(nd->fd, ne2000_can_receive, ne2000_receive, s);
 }

hw/pc.c

@@ -58,50 +58,69 @@
 int speaker_data_on;
 int dummy_refresh_clock;
 static fdctrl_t *floppy_controller;
+static RTCState *rtc_state;
 
 static void ioport80_write(void *opaque, uint32_t addr, uint32_t data)
 {
 }
 
+/* PC cmos mappings */
+
 #define REG_EQUIPMENT_BYTE          0x14
+#define REG_IBM_CENTURY_BYTE        0x32
+#define REG_IBM_PS2_CENTURY_BYTE    0x37
+
+
+static inline int to_bcd(RTCState *s, int a)
+{
+    return ((a / 10) << 4) | (a % 10);
+}
 
 static void cmos_init(int ram_size, int boot_device)
 {
-    RTCState *s = &rtc_state;
+    RTCState *s = rtc_state;
     int val;
     int fd0, fd1, nb;
-    
-    /* various important CMOS locations needed by PC/Bochs bios */
+    time_t ti;
+    struct tm *tm;
+
+    /* set the CMOS date */
+    time(&ti);
+    tm = gmtime(&ti);
+    rtc_set_date(s, tm);
+
+    val = to_bcd(s, (tm->tm_year / 100) + 19);
+    rtc_set_memory(s, REG_IBM_CENTURY_BYTE, val);
+    rtc_set_memory(s, REG_IBM_PS2_CENTURY_BYTE, val);
 
-    s->cmos_data[REG_EQUIPMENT_BYTE] = 0x02; /* FPU is there */
-    s->cmos_data[REG_EQUIPMENT_BYTE] |= 0x04; /* PS/2 mouse installed */
+    /* various important CMOS locations needed by PC/Bochs bios */
 
     /* memory size */
     val = (ram_size / 1024) - 1024;
     if (val > 65535)
         val = 65535;
-    s->cmos_data[0x17] = val;
-    s->cmos_data[0x18] = val >> 8;
-    s->cmos_data[0x30] = val;
-    s->cmos_data[0x31] = val >> 8;
+    rtc_set_memory(s, 0x17, val);
+    rtc_set_memory(s, 0x18, val >> 8);
+    rtc_set_memory(s, 0x30, val);
+    rtc_set_memory(s, 0x31, val >> 8);
 
     val = (ram_size / 65536) - ((16 * 1024 * 1024) / 65536);
     if (val > 65535)
         val = 65535;
-    s->cmos_data[0x34] = val;
-    s->cmos_data[0x35] = val >> 8;
+    rtc_set_memory(s, 0x34, val);
+    rtc_set_memory(s, 0x35, val >> 8);
     
     switch(boot_device) {
     case 'a':
     case 'b':
-        s->cmos_data[0x3d] = 0x01; /* floppy boot */
+        rtc_set_memory(s, 0x3d, 0x01); /* floppy boot */
         break;
     default:
     case 'c':
-        s->cmos_data[0x3d] = 0x02; /* hard drive boot */
+        rtc_set_memory(s, 0x3d, 0x02); /* hard drive boot */
         break;
     case 'd':
-        s->cmos_data[0x3d] = 0x03; /* CD-ROM boot */
+        rtc_set_memory(s, 0x3d, 0x03); /* CD-ROM boot */
         break;
     }
 
@@ -110,35 +129,38 @@ static void cmos_init(int ram_size, int boot_device)
     fd0 = fdctrl_get_drive_type(floppy_controller, 0);
     fd1 = fdctrl_get_drive_type(floppy_controller, 1);
 
-    s->cmos_data[0x10] = 0;
+    val = 0;
     switch (fd0) {
     case 0:
         /* 1.44 Mb 3"5 drive */
-        s->cmos_data[0x10] |= 0x40;
+        val |= 0x40;
         break;
     case 1:
         /* 2.88 Mb 3"5 drive */
-        s->cmos_data[0x10] |= 0x60;
+        val |= 0x60;
         break;
     case 2:
         /* 1.2 Mb 5"5 drive */
-        s->cmos_data[0x10] |= 0x20;
+        val |= 0x20;
         break;
     }
     switch (fd1) {
     case 0:
         /* 1.44 Mb 3"5 drive */
-        s->cmos_data[0x10] |= 0x04;
+        val |= 0x04;
         break;
     case 1:
         /* 2.88 Mb 3"5 drive */
-        s->cmos_data[0x10] |= 0x06;
+        val |= 0x06;
         break;
     case 2:
         /* 1.2 Mb 5"5 drive */
-        s->cmos_data[0x10] |= 0x02;
+        val |= 0x02;
         break;
     }
+    rtc_set_memory(s, 0x10, val);
+    
+    val = 0;
     nb = 0;
     if (fd0 < 3)
         nb++;
@@ -148,12 +170,16 @@ static void cmos_init(int ram_size, int boot_device)
     case 0:
         break;
     case 1:
-        s->cmos_data[REG_EQUIPMENT_BYTE] |= 0x01; /* 1 drive, ready for boot */
+        val |= 0x01; /* 1 drive, ready for boot */
         break;
     case 2:
-        s->cmos_data[REG_EQUIPMENT_BYTE] |= 0x41; /* 2 drives, ready for boot */
+        val |= 0x41; /* 2 drives, ready for boot */
         break;
     }
+    val |= 0x02; /* FPU is there */
+    val |= 0x04; /* PS/2 mouse installed */
+    rtc_set_memory(s, REG_EQUIPMENT_BYTE, val);
+
 }
 
 static void speaker_ioport_write(void *opaque, uint32_t addr, uint32_t val)
@@ -165,7 +191,7 @@ static void speaker_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 static uint32_t speaker_ioport_read(void *opaque, uint32_t addr)
 {
     int out;
-    out = pit_get_out(&pit_channels[2]);
+    out = pit_get_out(&pit_channels[2], qemu_get_clock(vm_clock));
     dummy_refresh_clock ^= 1;
     return (speaker_data_on << 1) | pit_channels[2].gate | (out << 5) |
       (dummy_refresh_clock << 4);
@@ -345,12 +371,12 @@ void pc_init(int ram_size, int vga_ram_size, int boot_device,
     vga_initialize(ds, phys_ram_base + ram_size, ram_size, 
                    vga_ram_size);
 
-    rtc_init(0x70, 8);
+    rtc_state = rtc_init(0x70, 8);
     register_ioport_read(0x61, 1, 1, speaker_ioport_read, NULL);
     register_ioport_write(0x61, 1, 1, speaker_ioport_write, NULL);
 
     pic_init();
-    pit_init(0x40);
+    pit_init(0x40, 0);
 
     fd = serial_open_device();
     serial_init(0x3f8, 4, fd);

hw/serial.c

@@ -288,7 +288,7 @@ SerialState *serial_init(int base, int irq, int fd)
     register_ioport_read(base, 8, 1, serial_ioport_read, s);
 
     if (fd != 0) {
-        add_fd_read_handler(fd, serial_can_receive1, serial_receive1, s);
+        qemu_add_fd_read_handler(fd, serial_can_receive1, serial_receive1, s);
         s->out_fd = fd;
     } else {
         serial_console = s;

hw/vga.c

@@ -1578,6 +1578,98 @@ static CPUWriteMemoryFunc *vga_mem_write[3] = {
     vga_mem_writel,
 };
 
+static void vga_save(QEMUFile *f, void *opaque)
+{
+    VGAState *s = opaque;
+    int i;
+
+    qemu_put_be32s(f, &s->latch);
+    qemu_put_8s(f, &s->sr_index);
+    qemu_put_buffer(f, s->sr, 8);
+    qemu_put_8s(f, &s->gr_index);
+    qemu_put_buffer(f, s->gr, 16);
+    qemu_put_8s(f, &s->ar_index);
+    qemu_put_buffer(f, s->ar, 21);
+    qemu_put_be32s(f, &s->ar_flip_flop);
+    qemu_put_8s(f, &s->cr_index);
+    qemu_put_buffer(f, s->cr, 256);
+    qemu_put_8s(f, &s->msr);
+    qemu_put_8s(f, &s->fcr);
+    qemu_put_8s(f, &s->st00);
+    qemu_put_8s(f, &s->st01);
+
+    qemu_put_8s(f, &s->dac_state);
+    qemu_put_8s(f, &s->dac_sub_index);
+    qemu_put_8s(f, &s->dac_read_index);
+    qemu_put_8s(f, &s->dac_write_index);
+    qemu_put_buffer(f, s->dac_cache, 3);
+    qemu_put_buffer(f, s->palette, 768);
+
+    qemu_put_be32s(f, &s->bank_offset);
+#ifdef CONFIG_BOCHS_VBE
+    qemu_put_byte(f, 1);
+    qemu_put_be16s(f, &s->vbe_index);
+    for(i = 0; i < VBE_DISPI_INDEX_NB; i++)
+        qemu_put_be16s(f, &s->vbe_regs[i]);
+    qemu_put_be32s(f, &s->vbe_start_addr);
+    qemu_put_be32s(f, &s->vbe_line_offset);
+    qemu_put_be32s(f, &s->vbe_bank_mask);
+#else
+    qemu_put_byte(f, 0);
+#endif
+}
+
+static int vga_load(QEMUFile *f, void *opaque, int version_id)
+{
+    VGAState *s = opaque;
+    int is_vbe, i;
+
+    if (version_id != 1)
+        return -EINVAL;
+
+    qemu_get_be32s(f, &s->latch);
+    qemu_get_8s(f, &s->sr_index);
+    qemu_get_buffer(f, s->sr, 8);
+    qemu_get_8s(f, &s->gr_index);
+    qemu_get_buffer(f, s->gr, 16);
+    qemu_get_8s(f, &s->ar_index);
+    qemu_get_buffer(f, s->ar, 21);
+    qemu_get_be32s(f, &s->ar_flip_flop);
+    qemu_get_8s(f, &s->cr_index);
+    qemu_get_buffer(f, s->cr, 256);
+    qemu_get_8s(f, &s->msr);
+    qemu_get_8s(f, &s->fcr);
+    qemu_get_8s(f, &s->st00);
+    qemu_get_8s(f, &s->st01);
+
+    qemu_get_8s(f, &s->dac_state);
+    qemu_get_8s(f, &s->dac_sub_index);
+    qemu_get_8s(f, &s->dac_read_index);
+    qemu_get_8s(f, &s->dac_write_index);
+    qemu_get_buffer(f, s->dac_cache, 3);
+    qemu_get_buffer(f, s->palette, 768);
+
+    qemu_get_be32s(f, &s->bank_offset);
+    is_vbe = qemu_get_byte(f);
+#ifdef CONFIG_BOCHS_VBE
+    if (!is_vbe)
+        return -EINVAL;
+    qemu_get_be16s(f, &s->vbe_index);
+    for(i = 0; i < VBE_DISPI_INDEX_NB; i++)
+        qemu_get_be16s(f, &s->vbe_regs[i]);
+    qemu_get_be32s(f, &s->vbe_start_addr);
+    qemu_get_be32s(f, &s->vbe_line_offset);
+    qemu_get_be32s(f, &s->vbe_bank_mask);
+#else
+    if (is_vbe)
+        return -EINVAL;
+#endif
+
+    /* force refresh */
+    s->graphic_mode = -1;
+    return 0;
+}
+
 int vga_initialize(DisplayState *ds, uint8_t *vga_ram_base, 
                    unsigned long vga_ram_offset, int vga_ram_size)
 {
@@ -1614,6 +1706,8 @@ int vga_initialize(DisplayState *ds, uint8_t *vga_ram_base,
     s->vram_size = vga_ram_size;
     s->ds = ds;
 
+    register_savevm("vga", 0, 1, vga_save, vga_load, s);
+
     register_ioport_write(0x3c0, 16, 1, vga_ioport_write, s);
 
     register_ioport_write(0x3b4, 2, 1, vga_ioport_write, s);