2 * QEMU PC System Emulator
4 * Copyright (c) 2003 Fabrice Bellard
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
42 #include <sys/ioctl.h>
43 #include <sys/socket.h>
45 #include <linux/if_tun.h>
50 #define DEBUG_LOGFILE "/tmp/vl.log"
51 #define DEFAULT_NETWORK_SCRIPT "/etc/vl-ifup"
53 //#define DEBUG_UNUSED_IOPORT
55 #define PHYS_RAM_BASE 0xa8000000
56 #define KERNEL_LOAD_ADDR 0x00100000
57 #define INITRD_LOAD_ADDR 0x00400000
58 #define KERNEL_PARAMS_ADDR 0x00090000
60 /* from plex86 (BSD license) */
61 struct __attribute__ ((packed)) linux_params {
62 // For 0x00..0x3f, see 'struct screen_info' in linux/include/linux/tty.h.
63 // I just padded out the VESA parts, rather than define them.
65 /* 0x000 */ uint8_t orig_x;
66 /* 0x001 */ uint8_t orig_y;
67 /* 0x002 */ uint16_t ext_mem_k;
68 /* 0x004 */ uint16_t orig_video_page;
69 /* 0x006 */ uint8_t orig_video_mode;
70 /* 0x007 */ uint8_t orig_video_cols;
71 /* 0x008 */ uint16_t unused1;
72 /* 0x00a */ uint16_t orig_video_ega_bx;
73 /* 0x00c */ uint16_t unused2;
74 /* 0x00e */ uint8_t orig_video_lines;
75 /* 0x00f */ uint8_t orig_video_isVGA;
76 /* 0x010 */ uint16_t orig_video_points;
77 /* 0x012 */ uint8_t pad0[0x20 - 0x12]; // VESA info.
78 /* 0x020 */ uint16_t cl_magic; // Commandline magic number (0xA33F)
79 /* 0x022 */ uint16_t cl_offset; // Commandline offset. Address of commandline
80 // is calculated as 0x90000 + cl_offset, bu
81 // only if cl_magic == 0xA33F.
82 /* 0x024 */ uint8_t pad1[0x40 - 0x24]; // VESA info.
84 /* 0x040 */ uint8_t apm_bios_info[20]; // struct apm_bios_info
85 /* 0x054 */ uint8_t pad2[0x80 - 0x54];
87 // Following 2 from 'struct drive_info_struct' in drivers/block/cciss.h.
88 // Might be truncated?
89 /* 0x080 */ uint8_t hd0_info[16]; // hd0-disk-parameter from intvector 0x41
90 /* 0x090 */ uint8_t hd1_info[16]; // hd1-disk-parameter from intvector 0x46
92 // System description table truncated to 16 bytes
93 // From 'struct sys_desc_table_struct' in linux/arch/i386/kernel/setup.c.
94 /* 0x0a0 */ uint16_t sys_description_len;
95 /* 0x0a2 */ uint8_t sys_description_table[14];
97 // [1] machine submodel id
101 /* 0x0b0 */ uint8_t pad3[0x1e0 - 0xb0];
102 /* 0x1e0 */ uint32_t alt_mem_k;
103 /* 0x1e4 */ uint8_t pad4[4];
104 /* 0x1e8 */ uint8_t e820map_entries;
105 /* 0x1e9 */ uint8_t eddbuf_entries; // EDD_NR
106 /* 0x1ea */ uint8_t pad5[0x1f1 - 0x1ea];
107 /* 0x1f1 */ uint8_t setup_sects; // size of setup.S, number of sectors
108 /* 0x1f2 */ uint16_t mount_root_rdonly; // MOUNT_ROOT_RDONLY (if !=0)
109 /* 0x1f4 */ uint16_t sys_size; // size of compressed kernel-part in the
110 // (b)zImage-file (in 16 byte units, rounded up)
111 /* 0x1f6 */ uint16_t swap_dev; // (unused AFAIK)
112 /* 0x1f8 */ uint16_t ramdisk_flags;
113 /* 0x1fa */ uint16_t vga_mode; // (old one)
114 /* 0x1fc */ uint16_t orig_root_dev; // (high=Major, low=minor)
115 /* 0x1fe */ uint8_t pad6[1];
116 /* 0x1ff */ uint8_t aux_device_info;
117 /* 0x200 */ uint16_t jump_setup; // Jump to start of setup code,
118 // aka "reserved" field.
119 /* 0x202 */ uint8_t setup_signature[4]; // Signature for SETUP-header, ="HdrS"
120 /* 0x206 */ uint16_t header_format_version; // Version number of header format;
121 /* 0x208 */ uint8_t setup_S_temp0[8]; // Used by setup.S for communication with
122 // boot loaders, look there.
123 /* 0x210 */ uint8_t loader_type;
128 // T=2: bootsect-loader
132 /* 0x211 */ uint8_t loadflags;
133 // bit0 = 1: kernel is loaded high (bzImage)
134 // bit7 = 1: Heap and pointer (see below) set by boot
136 /* 0x212 */ uint16_t setup_S_temp1;
137 /* 0x214 */ uint32_t kernel_start;
138 /* 0x218 */ uint32_t initrd_start;
139 /* 0x21c */ uint32_t initrd_size;
140 /* 0x220 */ uint8_t setup_S_temp2[4];
141 /* 0x224 */ uint16_t setup_S_heap_end_pointer;
142 /* 0x226 */ uint8_t pad7[0x2d0 - 0x226];
144 /* 0x2d0 : Int 15, ax=e820 memory map. */
145 // (linux/include/asm-i386/e820.h, 'struct e820entry')
148 #define E820_RESERVED 2
149 #define E820_ACPI 3 /* usable as RAM once ACPI tables have been read */
157 /* 0x550 */ uint8_t pad8[0x600 - 0x550];
159 // BIOS Enhanced Disk Drive Services.
160 // (From linux/include/asm-i386/edd.h, 'struct edd_info')
161 // Each 'struct edd_info is 78 bytes, times a max of 6 structs in array.
162 /* 0x600 */ uint8_t eddbuf[0x7d4 - 0x600];
164 /* 0x7d4 */ uint8_t pad9[0x800 - 0x7d4];
165 /* 0x800 */ uint8_t commandline[0x800];
168 uint64_t gdt_table[256];
169 uint64_t idt_table[48];
172 #define KERNEL_CS 0x10
173 #define KERNEL_DS 0x18
175 typedef void (IOPortWriteFunc)(CPUX86State *env, uint32_t address, uint32_t data);
176 typedef uint32_t (IOPortReadFunc)(CPUX86State *env, uint32_t address);
178 #define MAX_IOPORTS 1024
180 char phys_ram_file[1024];
181 CPUX86State *global_env;
182 CPUX86State *cpu_single_env;
183 FILE *logfile = NULL;
185 IOPortReadFunc *ioport_readb_table[MAX_IOPORTS];
186 IOPortWriteFunc *ioport_writeb_table[MAX_IOPORTS];
187 IOPortReadFunc *ioport_readw_table[MAX_IOPORTS];
188 IOPortWriteFunc *ioport_writew_table[MAX_IOPORTS];
190 /***********************************************************/
193 uint32_t default_ioport_readb(CPUX86State *env, uint32_t address)
195 #ifdef DEBUG_UNUSED_IOPORT
196 fprintf(stderr, "inb: port=0x%04x\n", address);
201 void default_ioport_writeb(CPUX86State *env, uint32_t address, uint32_t data)
203 #ifdef DEBUG_UNUSED_IOPORT
204 fprintf(stderr, "outb: port=0x%04x data=0x%02x\n", address, data);
208 /* default is to make two byte accesses */
209 uint32_t default_ioport_readw(CPUX86State *env, uint32_t address)
212 data = ioport_readb_table[address](env, address);
213 data |= ioport_readb_table[address + 1](env, address + 1) << 8;
217 void default_ioport_writew(CPUX86State *env, uint32_t address, uint32_t data)
219 ioport_writeb_table[address](env, address, data & 0xff);
220 ioport_writeb_table[address + 1](env, address + 1, (data >> 8) & 0xff);
223 void init_ioports(void)
227 for(i = 0; i < MAX_IOPORTS; i++) {
228 ioport_readb_table[i] = default_ioport_readb;
229 ioport_writeb_table[i] = default_ioport_writeb;
230 ioport_readw_table[i] = default_ioport_readw;
231 ioport_writew_table[i] = default_ioport_writew;
235 int register_ioport_readb(int start, int length, IOPortReadFunc *func)
239 for(i = start; i < start + length; i++)
240 ioport_readb_table[i] = func;
244 int register_ioport_writeb(int start, int length, IOPortWriteFunc *func)
248 for(i = start; i < start + length; i++)
249 ioport_writeb_table[i] = func;
253 int register_ioport_readw(int start, int length, IOPortReadFunc *func)
257 for(i = start; i < start + length; i += 2)
258 ioport_readw_table[i] = func;
262 int register_ioport_writew(int start, int length, IOPortWriteFunc *func)
266 for(i = start; i < start + length; i += 2)
267 ioport_writew_table[i] = func;
271 void pstrcpy(char *buf, int buf_size, const char *str)
281 if (c == 0 || q >= buf + buf_size - 1)
288 /* strcat and truncate. */
289 char *pstrcat(char *buf, int buf_size, const char *s)
294 pstrcpy(buf + len, buf_size - len, s);
298 int load_kernel(const char *filename, uint8_t *addr)
300 int fd, size, setup_sects;
301 uint8_t bootsect[512];
303 fd = open(filename, O_RDONLY);
306 if (read(fd, bootsect, 512) != 512)
308 setup_sects = bootsect[0x1F1];
311 /* skip 16 bit setup code */
312 lseek(fd, (setup_sects + 1) * 512, SEEK_SET);
313 size = read(fd, addr, 16 * 1024 * 1024);
323 /* return the size or -1 if error */
324 int load_image(const char *filename, uint8_t *addr)
327 fd = open(filename, O_RDONLY);
330 size = lseek(fd, 0, SEEK_END);
331 lseek(fd, 0, SEEK_SET);
332 if (read(fd, addr, size) != size) {
340 void cpu_x86_outb(CPUX86State *env, int addr, int val)
342 ioport_writeb_table[addr & (MAX_IOPORTS - 1)](env, addr, val);
345 void cpu_x86_outw(CPUX86State *env, int addr, int val)
347 ioport_writew_table[addr & (MAX_IOPORTS - 1)](env, addr, val);
350 void cpu_x86_outl(CPUX86State *env, int addr, int val)
352 fprintf(stderr, "outl: port=0x%04x, data=%08x\n", addr, val);
355 int cpu_x86_inb(CPUX86State *env, int addr)
357 return ioport_readb_table[addr & (MAX_IOPORTS - 1)](env, addr);
360 int cpu_x86_inw(CPUX86State *env, int addr)
362 return ioport_readw_table[addr & (MAX_IOPORTS - 1)](env, addr);
365 int cpu_x86_inl(CPUX86State *env, int addr)
367 fprintf(stderr, "inl: port=0x%04x\n", addr);
371 /***********************************************************/
372 void ioport80_write(CPUX86State *env, uint32_t addr, uint32_t data)
376 void hw_error(const char *fmt, ...)
381 fprintf(stderr, "qemu: hardware error: ");
382 vfprintf(stderr, fmt, ap);
383 fprintf(stderr, "\n");
385 cpu_x86_dump_state(global_env, stderr, X86_DUMP_FPU | X86_DUMP_CCOP);
391 /***********************************************************/
393 static uint8_t vga_index;
394 static uint8_t vga_regs[256];
395 static int last_cursor_pos;
397 void update_console_messages(void)
399 int c, i, cursor_pos, eol;
401 cursor_pos = vga_regs[0x0f] | (vga_regs[0x0e] << 8);
403 for(i = last_cursor_pos; i < cursor_pos; i++) {
404 c = phys_ram_base[0xb8000 + (i) * 2];
415 last_cursor_pos = cursor_pos;
418 /* just to see first Linux console messages, we intercept cursor position */
419 void vga_ioport_write(CPUX86State *env, uint32_t addr, uint32_t data)
426 vga_regs[vga_index] = data;
427 if (vga_index == 0x0f)
428 update_console_messages();
434 /***********************************************************/
437 #define RTC_SECONDS 0
438 #define RTC_SECONDS_ALARM 1
439 #define RTC_MINUTES 2
440 #define RTC_MINUTES_ALARM 3
442 #define RTC_HOURS_ALARM 5
443 #define RTC_ALARM_DONT_CARE 0xC0
445 #define RTC_DAY_OF_WEEK 6
446 #define RTC_DAY_OF_MONTH 7
455 /* PC cmos mappings */
456 #define REG_EQUIPMENT_BYTE 0x14
458 uint8_t cmos_data[128];
461 void cmos_ioport_write(CPUX86State *env, uint32_t addr, uint32_t data)
464 cmos_index = data & 0x7f;
468 uint32_t cmos_ioport_read(CPUX86State *env, uint32_t addr)
475 /* toggle update-in-progress bit for Linux (same hack as
477 ret = cmos_data[cmos_index];
478 if (cmos_index == RTC_REG_A)
479 cmos_data[RTC_REG_A] ^= 0x80;
480 else if (cmos_index == RTC_REG_C)
481 cmos_data[RTC_REG_C] = 0x00;
487 static inline int to_bcd(int a)
489 return ((a / 10) << 4) | (a % 10);
499 cmos_data[RTC_SECONDS] = to_bcd(tm->tm_sec);
500 cmos_data[RTC_MINUTES] = to_bcd(tm->tm_min);
501 cmos_data[RTC_HOURS] = to_bcd(tm->tm_hour);
502 cmos_data[RTC_DAY_OF_WEEK] = to_bcd(tm->tm_wday);
503 cmos_data[RTC_DAY_OF_MONTH] = to_bcd(tm->tm_mday);
504 cmos_data[RTC_MONTH] = to_bcd(tm->tm_mon);
505 cmos_data[RTC_YEAR] = to_bcd(tm->tm_year % 100);
507 cmos_data[RTC_REG_A] = 0x26;
508 cmos_data[RTC_REG_B] = 0x02;
509 cmos_data[RTC_REG_C] = 0x00;
510 cmos_data[RTC_REG_D] = 0x80;
512 cmos_data[REG_EQUIPMENT_BYTE] = 0x02; /* FPU is there */
514 register_ioport_writeb(0x70, 2, cmos_ioport_write);
515 register_ioport_readb(0x70, 2, cmos_ioport_read);
518 /***********************************************************/
519 /* 8259 pic emulation */
521 typedef struct PicState {
522 uint8_t last_irr; /* edge detection */
523 uint8_t irr; /* interrupt request register */
524 uint8_t imr; /* interrupt mask register */
525 uint8_t isr; /* interrupt service register */
526 uint8_t priority_add; /* used to compute irq priority */
528 uint8_t read_reg_select;
529 uint8_t special_mask;
532 uint8_t rotate_on_autoeoi;
533 uint8_t init4; /* true if 4 byte init */
536 /* 0 is master pic, 1 is slave pic */
538 int pic_irq_requested;
540 /* set irq level. If an edge is detected, then the IRR is set to 1 */
541 static inline void pic_set_irq1(PicState *s, int irq, int level)
546 if ((s->last_irr & mask) == 0)
550 s->last_irr &= ~mask;
554 static inline int get_priority(PicState *s, int mask)
560 while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0)
565 /* return the pic wanted interrupt. return -1 if none */
566 static int pic_get_irq(PicState *s)
568 int mask, cur_priority, priority;
570 mask = s->irr & ~s->imr;
571 priority = get_priority(s, mask);
574 /* compute current priority */
575 cur_priority = get_priority(s, s->isr);
576 if (priority > cur_priority) {
577 /* higher priority found: an irq should be generated */
584 void pic_set_irq(int irq, int level)
586 pic_set_irq1(&pics[irq >> 3], irq & 7, level);
589 /* can be called at any time outside cpu_exec() to raise irqs if
591 void pic_handle_irq(void)
595 /* first look at slave pic */
596 irq2 = pic_get_irq(&pics[1]);
598 /* if irq request by slave pic, signal master PIC */
599 pic_set_irq1(&pics[0], 2, 1);
600 pic_set_irq1(&pics[0], 2, 0);
602 /* look at requested irq */
603 irq = pic_get_irq(&pics[0]);
607 pic_irq_requested = 8 + irq2;
609 /* from master pic */
610 pic_irq_requested = irq;
612 global_env->hard_interrupt_request = 1;
616 int cpu_x86_get_pic_interrupt(CPUX86State *env)
618 int irq, irq2, intno;
620 /* signal the pic that the irq was acked by the CPU */
621 irq = pic_irq_requested;
624 pics[1].isr |= (1 << irq2);
625 pics[1].irr &= ~(1 << irq2);
627 intno = pics[1].irq_base + irq2;
629 intno = pics[0].irq_base + irq;
631 pics[0].isr |= (1 << irq);
632 pics[0].irr &= ~(1 << irq);
636 void pic_ioport_write(CPUX86State *env, uint32_t addr, uint32_t val)
641 s = &pics[addr >> 7];
646 memset(s, 0, sizeof(PicState));
650 hw_error("single mode not supported");
652 hw_error("level sensitive irq not supported");
653 } else if (val & 0x08) {
655 s->read_reg_select = val & 1;
657 s->special_mask = (val >> 5) & 1;
662 s->rotate_on_autoeoi = val >> 7;
664 case 0x20: /* end of interrupt */
666 priority = get_priority(s, s->isr);
668 s->isr &= ~(1 << ((priority + s->priority_add) & 7));
671 s->priority_add = (s->priority_add + 1) & 7;
675 s->isr &= ~(1 << priority);
678 s->priority_add = (val + 1) & 7;
682 s->isr &= ~(1 << priority);
683 s->priority_add = (priority + 1) & 7;
688 switch(s->init_state) {
694 s->irq_base = val & 0xf8;
705 s->auto_eoi = (val >> 1) & 1;
712 uint32_t pic_ioport_read(CPUX86State *env, uint32_t addr)
715 s = &pics[addr >> 7];
718 if (s->read_reg_select)
729 register_ioport_writeb(0x20, 2, pic_ioport_write);
730 register_ioport_readb(0x20, 2, pic_ioport_read);
731 register_ioport_writeb(0xa0, 2, pic_ioport_write);
732 register_ioport_readb(0xa0, 2, pic_ioport_read);
735 /***********************************************************/
736 /* 8253 PIT emulation */
738 #define PIT_FREQ 1193182
740 #define RW_STATE_LSB 0
741 #define RW_STATE_MSB 1
742 #define RW_STATE_WORD0 2
743 #define RW_STATE_WORD1 3
744 #define RW_STATE_LATCHED_WORD0 4
745 #define RW_STATE_LATCHED_WORD1 5
747 typedef struct PITChannelState {
749 uint16_t latched_count;
752 uint8_t bcd; /* not supported */
753 uint8_t gate; /* timer start */
754 int64_t count_load_time;
757 PITChannelState pit_channels[3];
760 int64_t ticks_per_sec;
762 int64_t get_clock(void)
765 gettimeofday(&tv, NULL);
766 return tv.tv_sec * 1000000LL + tv.tv_usec;
769 int64_t cpu_get_ticks(void)
772 asm("rdtsc" : "=A" (val));
776 void cpu_calibrate_ticks(void)
781 ticks = cpu_get_ticks();
783 usec = get_clock() - usec;
784 ticks = cpu_get_ticks() - ticks;
785 ticks_per_sec = (ticks * 1000000LL + (usec >> 1)) / usec;
788 static int pit_get_count(PITChannelState *s)
793 d = ((cpu_get_ticks() - s->count_load_time) * PIT_FREQ) /
800 counter = (s->count - d) & 0xffff;
803 counter = s->count - (d % s->count);
809 /* get pit output bit */
810 static int pit_get_out(PITChannelState *s)
815 d = ((cpu_get_ticks() - s->count_load_time) * PIT_FREQ) /
820 out = (d >= s->count);
823 out = (d < s->count);
826 if ((d % s->count) == 0 && d != 0)
832 out = (d % s->count) < (s->count >> 1);
836 out = (d == s->count);
842 void pit_ioport_write(CPUX86State *env, uint32_t addr, uint32_t val)
852 s = &pit_channels[channel];
853 access = (val >> 4) & 3;
856 s->latched_count = pit_get_count(s);
857 s->rw_state = RW_STATE_LATCHED_WORD0;
860 s->rw_state = access - 1 + RW_STATE_LSB;
863 s->mode = (val >> 1) & 7;
866 s = &pit_channels[addr];
867 switch(s->rw_state) {
869 s->count_load_time = cpu_get_ticks();
873 s->count_load_time = cpu_get_ticks();
874 s->count = (val << 8);
878 if (s->rw_state & 1) {
879 s->count_load_time = cpu_get_ticks();
880 s->count = (s->latched_count & 0xff) | (val << 8);
882 s->latched_count = val;
890 uint32_t pit_ioport_read(CPUX86State *env, uint32_t addr)
896 s = &pit_channels[addr];
897 switch(s->rw_state) {
902 count = pit_get_count(s);
904 ret = (count >> 8) & 0xff;
911 case RW_STATE_LATCHED_WORD0:
912 case RW_STATE_LATCHED_WORD1:
914 ret = s->latched_count >> 8;
916 ret = s->latched_count & 0xff;
923 void speaker_ioport_write(CPUX86State *env, uint32_t addr, uint32_t val)
925 speaker_data_on = (val >> 1) & 1;
926 pit_channels[2].gate = val & 1;
929 uint32_t speaker_ioport_read(CPUX86State *env, uint32_t addr)
932 out = pit_get_out(&pit_channels[2]);
933 return (speaker_data_on << 1) | pit_channels[2].gate | (out << 5);
938 pit_channels[0].gate = 1;
939 pit_channels[1].gate = 1;
940 pit_channels[2].gate = 0;
942 register_ioport_writeb(0x40, 4, pit_ioport_write);
943 register_ioport_readb(0x40, 3, pit_ioport_read);
945 register_ioport_readb(0x61, 1, speaker_ioport_read);
946 register_ioport_writeb(0x61, 1, speaker_ioport_write);
947 cpu_calibrate_ticks();
950 /***********************************************************/
951 /* serial port emulation */
955 #define UART_LCR_DLAB 0x80 /* Divisor latch access bit */
957 #define UART_IER_MSI 0x08 /* Enable Modem status interrupt */
958 #define UART_IER_RLSI 0x04 /* Enable receiver line status interrupt */
959 #define UART_IER_THRI 0x02 /* Enable Transmitter holding register int. */
960 #define UART_IER_RDI 0x01 /* Enable receiver data interrupt */
962 #define UART_IIR_NO_INT 0x01 /* No interrupts pending */
963 #define UART_IIR_ID 0x06 /* Mask for the interrupt ID */
965 #define UART_IIR_MSI 0x00 /* Modem status interrupt */
966 #define UART_IIR_THRI 0x02 /* Transmitter holding register empty */
967 #define UART_IIR_RDI 0x04 /* Receiver data interrupt */
968 #define UART_IIR_RLSI 0x06 /* Receiver line status interrupt */
970 #define UART_LSR_TEMT 0x40 /* Transmitter empty */
971 #define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */
972 #define UART_LSR_BI 0x10 /* Break interrupt indicator */
973 #define UART_LSR_FE 0x08 /* Frame error indicator */
974 #define UART_LSR_PE 0x04 /* Parity error indicator */
975 #define UART_LSR_OE 0x02 /* Overrun error indicator */
976 #define UART_LSR_DR 0x01 /* Receiver data ready */
978 typedef struct SerialState {
980 uint8_t rbr; /* receive register */
982 uint8_t iir; /* read only */
985 uint8_t lsr; /* read only */
990 SerialState serial_ports[1];
992 void serial_update_irq(void)
994 SerialState *s = &serial_ports[0];
996 if ((s->lsr & UART_LSR_DR) && (s->ier & UART_IER_RDI)) {
997 s->iir = UART_IIR_RDI;
998 } else if ((s->lsr & UART_LSR_THRE) && (s->ier & UART_IER_THRI)) {
999 s->iir = UART_IIR_THRI;
1001 s->iir = UART_IIR_NO_INT;
1003 if (s->iir != UART_IIR_NO_INT) {
1004 pic_set_irq(UART_IRQ, 1);
1006 pic_set_irq(UART_IRQ, 0);
1010 void serial_ioport_write(CPUX86State *env, uint32_t addr, uint32_t val)
1012 SerialState *s = &serial_ports[0];
1020 if (s->lcr & UART_LCR_DLAB) {
1021 s->divider = (s->divider & 0xff00) | val;
1023 s->lsr &= ~UART_LSR_THRE;
1024 serial_update_irq();
1028 ret = write(1, &ch, 1);
1030 s->lsr |= UART_LSR_THRE;
1031 s->lsr |= UART_LSR_TEMT;
1032 serial_update_irq();
1036 if (s->lcr & UART_LCR_DLAB) {
1037 s->divider = (s->divider & 0x00ff) | (val << 8);
1040 serial_update_irq();
1062 uint32_t serial_ioport_read(CPUX86State *env, uint32_t addr)
1064 SerialState *s = &serial_ports[0];
1071 if (s->lcr & UART_LCR_DLAB) {
1072 ret = s->divider & 0xff;
1075 s->lsr &= ~(UART_LSR_DR | UART_LSR_BI);
1076 serial_update_irq();
1080 if (s->lcr & UART_LCR_DLAB) {
1081 ret = (s->divider >> 8) & 0xff;
1108 #define TERM_ESCAPE 0x01 /* ctrl-a is used for escape */
1109 static int term_got_escape;
1111 void term_print_help(void)
1114 "C-a h print this help\n"
1115 "C-a x exit emulatior\n"
1116 "C-a b send break (magic sysrq)\n"
1117 "C-a C-a send C-a\n"
1121 /* called when a char is received */
1122 void serial_received_byte(SerialState *s, int ch)
1124 if (term_got_escape) {
1125 term_got_escape = 0;
1136 s->lsr |= UART_LSR_BI | UART_LSR_DR;
1137 serial_update_irq();
1142 } else if (ch == TERM_ESCAPE) {
1143 term_got_escape = 1;
1147 s->lsr |= UART_LSR_DR;
1148 serial_update_irq();
1152 /* init terminal so that we can grab keys */
1153 static struct termios oldtty;
1155 static void term_exit(void)
1157 tcsetattr (0, TCSANOW, &oldtty);
1160 static void term_init(void)
1164 tcgetattr (0, &tty);
1167 tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
1168 |INLCR|IGNCR|ICRNL|IXON);
1169 tty.c_oflag |= OPOST;
1170 tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN|ISIG);
1171 tty.c_cflag &= ~(CSIZE|PARENB);
1174 tty.c_cc[VTIME] = 0;
1176 tcsetattr (0, TCSANOW, &tty);
1180 fcntl(0, F_SETFL, O_NONBLOCK);
1183 void serial_init(void)
1185 SerialState *s = &serial_ports[0];
1187 s->lsr = UART_LSR_TEMT | UART_LSR_THRE;
1189 register_ioport_writeb(0x3f8, 8, serial_ioport_write);
1190 register_ioport_readb(0x3f8, 8, serial_ioport_read);
1195 /***********************************************************/
1196 /* ne2000 emulation */
1198 //#define DEBUG_NE2000
1200 #define NE2000_IOPORT 0x300
1201 #define NE2000_IRQ 9
1203 #define MAX_ETH_FRAME_SIZE 1514
1205 #define E8390_CMD 0x00 /* The command register (for all pages) */
1206 /* Page 0 register offsets. */
1207 #define EN0_CLDALO 0x01 /* Low byte of current local dma addr RD */
1208 #define EN0_STARTPG 0x01 /* Starting page of ring bfr WR */
1209 #define EN0_CLDAHI 0x02 /* High byte of current local dma addr RD */
1210 #define EN0_STOPPG 0x02 /* Ending page +1 of ring bfr WR */
1211 #define EN0_BOUNDARY 0x03 /* Boundary page of ring bfr RD WR */
1212 #define EN0_TSR 0x04 /* Transmit status reg RD */
1213 #define EN0_TPSR 0x04 /* Transmit starting page WR */
1214 #define EN0_NCR 0x05 /* Number of collision reg RD */
1215 #define EN0_TCNTLO 0x05 /* Low byte of tx byte count WR */
1216 #define EN0_FIFO 0x06 /* FIFO RD */
1217 #define EN0_TCNTHI 0x06 /* High byte of tx byte count WR */
1218 #define EN0_ISR 0x07 /* Interrupt status reg RD WR */
1219 #define EN0_CRDALO 0x08 /* low byte of current remote dma address RD */
1220 #define EN0_RSARLO 0x08 /* Remote start address reg 0 */
1221 #define EN0_CRDAHI 0x09 /* high byte, current remote dma address RD */
1222 #define EN0_RSARHI 0x09 /* Remote start address reg 1 */
1223 #define EN0_RCNTLO 0x0a /* Remote byte count reg WR */
1224 #define EN0_RCNTHI 0x0b /* Remote byte count reg WR */
1225 #define EN0_RSR 0x0c /* rx status reg RD */
1226 #define EN0_RXCR 0x0c /* RX configuration reg WR */
1227 #define EN0_TXCR 0x0d /* TX configuration reg WR */
1228 #define EN0_COUNTER0 0x0d /* Rcv alignment error counter RD */
1229 #define EN0_DCFG 0x0e /* Data configuration reg WR */
1230 #define EN0_COUNTER1 0x0e /* Rcv CRC error counter RD */
1231 #define EN0_IMR 0x0f /* Interrupt mask reg WR */
1232 #define EN0_COUNTER2 0x0f /* Rcv missed frame error counter RD */
1234 #define EN1_PHYS 0x11
1235 #define EN1_CURPAG 0x17
1236 #define EN1_MULT 0x18
1238 /* Register accessed at EN_CMD, the 8390 base addr. */
1239 #define E8390_STOP 0x01 /* Stop and reset the chip */
1240 #define E8390_START 0x02 /* Start the chip, clear reset */
1241 #define E8390_TRANS 0x04 /* Transmit a frame */
1242 #define E8390_RREAD 0x08 /* Remote read */
1243 #define E8390_RWRITE 0x10 /* Remote write */
1244 #define E8390_NODMA 0x20 /* Remote DMA */
1245 #define E8390_PAGE0 0x00 /* Select page chip registers */
1246 #define E8390_PAGE1 0x40 /* using the two high-order bits */
1247 #define E8390_PAGE2 0x80 /* Page 3 is invalid. */
1249 /* Bits in EN0_ISR - Interrupt status register */
1250 #define ENISR_RX 0x01 /* Receiver, no error */
1251 #define ENISR_TX 0x02 /* Transmitter, no error */
1252 #define ENISR_RX_ERR 0x04 /* Receiver, with error */
1253 #define ENISR_TX_ERR 0x08 /* Transmitter, with error */
1254 #define ENISR_OVER 0x10 /* Receiver overwrote the ring */
1255 #define ENISR_COUNTERS 0x20 /* Counters need emptying */
1256 #define ENISR_RDC 0x40 /* remote dma complete */
1257 #define ENISR_RESET 0x80 /* Reset completed */
1258 #define ENISR_ALL 0x3f /* Interrupts we will enable */
1260 /* Bits in received packet status byte and EN0_RSR*/
1261 #define ENRSR_RXOK 0x01 /* Received a good packet */
1262 #define ENRSR_CRC 0x02 /* CRC error */
1263 #define ENRSR_FAE 0x04 /* frame alignment error */
1264 #define ENRSR_FO 0x08 /* FIFO overrun */
1265 #define ENRSR_MPA 0x10 /* missed pkt */
1266 #define ENRSR_PHY 0x20 /* physical/multicast address */
1267 #define ENRSR_DIS 0x40 /* receiver disable. set in monitor mode */
1268 #define ENRSR_DEF 0x80 /* deferring */
1270 /* Transmitted packet status, EN0_TSR. */
1271 #define ENTSR_PTX 0x01 /* Packet transmitted without error */
1272 #define ENTSR_ND 0x02 /* The transmit wasn't deferred. */
1273 #define ENTSR_COL 0x04 /* The transmit collided at least once. */
1274 #define ENTSR_ABT 0x08 /* The transmit collided 16 times, and was deferred. */
1275 #define ENTSR_CRS 0x10 /* The carrier sense was lost. */
1276 #define ENTSR_FU 0x20 /* A "FIFO underrun" occurred during transmit. */
1277 #define ENTSR_CDH 0x40 /* The collision detect "heartbeat" signal was lost. */
1278 #define ENTSR_OWC 0x80 /* There was an out-of-window collision. */
1280 #define NE2000_MEM_SIZE 32768
1282 typedef struct NE2000State {
1295 uint8_t phys[6]; /* mac address */
1297 uint8_t mult[8]; /* multicast mask array */
1298 uint8_t mem[NE2000_MEM_SIZE];
1301 NE2000State ne2000_state;
1303 char network_script[1024];
1305 void ne2000_reset(void)
1307 NE2000State *s = &ne2000_state;
1310 s->isr = ENISR_RESET;
1320 /* duplicate prom data */
1321 for(i = 15;i >= 0; i--) {
1322 s->mem[2 * i] = s->mem[i];
1323 s->mem[2 * i + 1] = s->mem[i];
1327 void ne2000_update_irq(NE2000State *s)
1330 isr = s->isr & s->imr;
1332 pic_set_irq(NE2000_IRQ, 1);
1334 pic_set_irq(NE2000_IRQ, 0);
1340 int fd, ret, pid, status;
1342 fd = open("/dev/net/tun", O_RDWR);
1344 fprintf(stderr, "warning: could not open /dev/net/tun: no virtual network emulation\n");
1347 memset(&ifr, 0, sizeof(ifr));
1348 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
1349 pstrcpy(ifr.ifr_name, IFNAMSIZ, "tun%d");
1350 ret = ioctl(fd, TUNSETIFF, (void *) &ifr);
1352 fprintf(stderr, "warning: could not configure /dev/net/tun: no virtual network emulation\n");
1356 printf("connected to host network interface: %s\n", ifr.ifr_name);
1357 fcntl(fd, F_SETFL, O_NONBLOCK);
1360 /* try to launch network init script */
1364 execl(network_script, network_script, ifr.ifr_name, NULL);
1367 while (waitpid(pid, &status, 0) != pid);
1368 if (!WIFEXITED(status) ||
1369 WEXITSTATUS(status) != 0) {
1370 fprintf(stderr, "%s: could not launch network script for '%s'\n",
1371 network_script, ifr.ifr_name);
1377 void net_send_packet(NE2000State *s, const uint8_t *buf, int size)
1380 printf("NE2000: sending packet size=%d\n", size);
1382 write(net_fd, buf, size);
1385 /* return true if the NE2000 can receive more data */
1386 int ne2000_can_receive(NE2000State *s)
1388 int avail, index, boundary;
1390 if (s->cmd & E8390_STOP)
1392 index = s->curpag << 8;
1393 boundary = s->boundary << 8;
1394 if (index < boundary)
1395 avail = boundary - index;
1397 avail = (s->stop - s->start) - (index - boundary);
1398 if (avail < (MAX_ETH_FRAME_SIZE + 4))
1403 void ne2000_receive(NE2000State *s, uint8_t *buf, int size)
1406 int total_len, next, avail, len, index;
1408 #if defined(DEBUG_NE2000)
1409 printf("NE2000: received len=%d\n", size);
1412 index = s->curpag << 8;
1413 /* 4 bytes for header */
1414 total_len = size + 4;
1415 /* address for next packet (4 bytes for CRC) */
1416 next = index + ((total_len + 4 + 255) & ~0xff);
1417 if (next >= s->stop)
1418 next -= (s->stop - s->start);
1419 /* prepare packet header */
1421 p[0] = ENRSR_RXOK; /* receive status */
1424 p[3] = total_len >> 8;
1427 /* write packet data */
1429 avail = s->stop - index;
1433 memcpy(s->mem + index, buf, len);
1436 if (index == s->stop)
1440 s->curpag = next >> 8;
1442 /* now we can signal we have receive something */
1444 ne2000_update_irq(s);
1447 void ne2000_ioport_write(CPUX86State *env, uint32_t addr, uint32_t val)
1449 NE2000State *s = &ne2000_state;
1454 printf("NE2000: write addr=0x%x val=0x%02x\n", addr, val);
1456 if (addr == E8390_CMD) {
1457 /* control register */
1459 if (val & E8390_START) {
1460 /* test specific case: zero length transfert */
1461 if ((val & (E8390_RREAD | E8390_RWRITE)) &&
1463 s->isr |= ENISR_RDC;
1464 ne2000_update_irq(s);
1466 if (val & E8390_TRANS) {
1467 net_send_packet(s, s->mem + (s->tpsr << 8), s->tcnt);
1468 /* signal end of transfert */
1471 ne2000_update_irq(s);
1476 offset = addr | (page << 4);
1479 s->start = val << 8;
1489 ne2000_update_irq(s);
1495 s->tcnt = (s->tcnt & 0xff00) | val;
1498 s->tcnt = (s->tcnt & 0x00ff) | (val << 8);
1501 s->rsar = (s->rsar & 0xff00) | val;
1504 s->rsar = (s->rsar & 0x00ff) | (val << 8);
1507 s->rcnt = (s->rcnt & 0xff00) | val;
1510 s->rcnt = (s->rcnt & 0x00ff) | (val << 8);
1517 ne2000_update_irq(s);
1519 case EN1_PHYS ... EN1_PHYS + 5:
1520 s->phys[offset - EN1_PHYS] = val;
1525 case EN1_MULT ... EN1_MULT + 7:
1526 s->mult[offset - EN1_MULT] = val;
1532 uint32_t ne2000_ioport_read(CPUX86State *env, uint32_t addr)
1534 NE2000State *s = &ne2000_state;
1535 int offset, page, ret;
1538 if (addr == E8390_CMD) {
1542 offset = addr | (page << 4);
1553 case EN1_PHYS ... EN1_PHYS + 5:
1554 ret = s->phys[offset - EN1_PHYS];
1559 case EN1_MULT ... EN1_MULT + 7:
1560 ret = s->mult[offset - EN1_MULT];
1568 printf("NE2000: read addr=0x%x val=%02x\n", addr, ret);
1573 void ne2000_asic_ioport_write(CPUX86State *env, uint32_t addr, uint32_t val)
1575 NE2000State *s = &ne2000_state;
1579 printf("NE2000: asic write val=0x%04x\n", val);
1581 p = s->mem + s->rsar;
1582 if (s->dcfg & 0x01) {
1595 if (s->rsar == s->stop)
1598 /* signal end of transfert */
1599 s->isr |= ENISR_RDC;
1600 ne2000_update_irq(s);
1604 uint32_t ne2000_asic_ioport_read(CPUX86State *env, uint32_t addr)
1606 NE2000State *s = &ne2000_state;
1610 p = s->mem + s->rsar;
1611 if (s->dcfg & 0x01) {
1613 ret = p[0] | (p[1] << 8);
1623 if (s->rsar == s->stop)
1626 /* signal end of transfert */
1627 s->isr |= ENISR_RDC;
1628 ne2000_update_irq(s);
1631 printf("NE2000: asic read val=0x%04x\n", ret);
1636 void ne2000_reset_ioport_write(CPUX86State *env, uint32_t addr, uint32_t val)
1638 /* nothing to do (end of reset pulse) */
1641 uint32_t ne2000_reset_ioport_read(CPUX86State *env, uint32_t addr)
1647 void ne2000_init(void)
1649 register_ioport_writeb(NE2000_IOPORT, 16, ne2000_ioport_write);
1650 register_ioport_readb(NE2000_IOPORT, 16, ne2000_ioport_read);
1652 register_ioport_writeb(NE2000_IOPORT + 0x10, 1, ne2000_asic_ioport_write);
1653 register_ioport_readb(NE2000_IOPORT + 0x10, 1, ne2000_asic_ioport_read);
1654 register_ioport_writew(NE2000_IOPORT + 0x10, 2, ne2000_asic_ioport_write);
1655 register_ioport_readw(NE2000_IOPORT + 0x10, 2, ne2000_asic_ioport_read);
1657 register_ioport_writeb(NE2000_IOPORT + 0x1f, 1, ne2000_reset_ioport_write);
1658 register_ioport_readb(NE2000_IOPORT + 0x1f, 1, ne2000_reset_ioport_read);
1662 /***********************************************************/
1663 /* cpu signal handler */
1664 static void host_segv_handler(int host_signum, siginfo_t *info,
1667 if (cpu_signal_handler(host_signum, info, puc))
1673 static int timer_irq_pending;
1675 static void host_alarm_handler(int host_signum, siginfo_t *info,
1678 /* just exit from the cpu to have a chance to handle timers */
1679 cpu_x86_interrupt(global_env);
1680 timer_irq_pending = 1;
1685 printf("Virtual Linux version " QEMU_VERSION ", Copyright (c) 2003 Fabrice Bellard\n"
1686 "usage: vl [-h] bzImage initrd [kernel parameters...]\n"
1688 "'bzImage' is a Linux kernel image (PAGE_OFFSET must be defined\n"
1689 "to 0x90000000 in asm/page.h and arch/i386/vmlinux.lds)\n"
1690 "'initrd' is an initrd image\n"
1691 "-m megs set virtual RAM size to megs MB\n"
1692 "-n script set network init script [default=%s]\n"
1693 "-d output log in /tmp/vl.log\n"
1695 "During emulation, use C-a h to get terminal commands:\n",
1696 DEFAULT_NETWORK_SCRIPT);
1701 int main(int argc, char **argv)
1703 int c, ret, initrd_size, i;
1704 struct linux_params *params;
1705 struct sigaction act;
1706 struct itimerval itv;
1709 /* we never want that malloc() uses mmap() */
1710 mallopt(M_MMAP_THRESHOLD, 4096 * 1024);
1712 phys_ram_size = 32 * 1024 * 1024;
1713 pstrcpy(network_script, sizeof(network_script), DEFAULT_NETWORK_SCRIPT);
1715 c = getopt(argc, argv, "hm:dn:");
1723 phys_ram_size = atoi(optarg) * 1024 * 1024;
1724 if (phys_ram_size <= 0)
1731 pstrcpy(network_script, sizeof(network_script), optarg);
1735 if (optind + 1 >= argc)
1740 logfile = fopen(DEBUG_LOGFILE, "w");
1742 perror(DEBUG_LOGFILE);
1745 setvbuf(logfile, NULL, _IOLBF, 0);
1748 /* init network tun interface */
1751 /* init the memory */
1752 strcpy(phys_ram_file, "/tmp/vlXXXXXX");
1753 if (mkstemp(phys_ram_file) < 0) {
1754 fprintf(stderr, "Could not create temporary memory file\n");
1757 phys_ram_fd = open(phys_ram_file, O_CREAT | O_TRUNC | O_RDWR, 0600);
1758 if (phys_ram_fd < 0) {
1759 fprintf(stderr, "Could not open temporary memory file\n");
1762 ftruncate(phys_ram_fd, phys_ram_size);
1763 unlink(phys_ram_file);
1764 phys_ram_base = mmap((void *)PHYS_RAM_BASE, phys_ram_size,
1765 PROT_WRITE | PROT_READ, MAP_SHARED | MAP_FIXED,
1767 if (phys_ram_base == MAP_FAILED) {
1768 fprintf(stderr, "Could not map physical memory\n");
1772 /* now we can load the kernel */
1773 ret = load_kernel(argv[optind], phys_ram_base + KERNEL_LOAD_ADDR);
1775 fprintf(stderr, "%s: could not load kernel\n", argv[optind]);
1780 initrd_size = load_image(argv[optind + 1], phys_ram_base + INITRD_LOAD_ADDR);
1781 if (initrd_size < 0) {
1782 fprintf(stderr, "%s: could not load initrd\n", argv[optind + 1]);
1786 /* init kernel params */
1787 params = (void *)(phys_ram_base + KERNEL_PARAMS_ADDR);
1788 memset(params, 0, sizeof(struct linux_params));
1789 params->mount_root_rdonly = 0;
1790 params->cl_magic = 0xA33F;
1791 params->cl_offset = params->commandline - (uint8_t *)params;
1792 params->ext_mem_k = (phys_ram_size / 1024) - 1024;
1793 for(i = optind + 2; i < argc; i++) {
1794 if (i != optind + 2)
1795 pstrcat(params->commandline, sizeof(params->commandline), " ");
1796 pstrcat(params->commandline, sizeof(params->commandline), argv[i]);
1798 params->loader_type = 0x01;
1799 if (initrd_size > 0) {
1800 params->initrd_start = INITRD_LOAD_ADDR;
1801 params->initrd_size = initrd_size;
1803 params->orig_video_lines = 25;
1804 params->orig_video_cols = 80;
1806 /* init basic PC hardware */
1808 register_ioport_writeb(0x80, 1, ioport80_write);
1810 register_ioport_writeb(0x3d4, 2, vga_ioport_write);
1818 /* setup cpu signal handlers for MMU / self modifying code handling */
1819 sigfillset(&act.sa_mask);
1820 act.sa_flags = SA_SIGINFO;
1821 act.sa_sigaction = host_segv_handler;
1822 sigaction(SIGSEGV, &act, NULL);
1823 sigaction(SIGBUS, &act, NULL);
1825 act.sa_sigaction = host_alarm_handler;
1826 sigaction(SIGALRM, &act, NULL);
1828 /* init CPU state */
1831 cpu_single_env = env;
1833 /* setup basic memory access */
1834 env->cr[0] = 0x00000033;
1835 cpu_x86_init_mmu(env);
1837 memset(params->idt_table, 0, sizeof(params->idt_table));
1839 params->gdt_table[2] = 0x00cf9a000000ffffLL; /* KERNEL_CS */
1840 params->gdt_table[3] = 0x00cf92000000ffffLL; /* KERNEL_DS */
1842 env->idt.base = (void *)params->idt_table;
1843 env->idt.limit = sizeof(params->idt_table) - 1;
1844 env->gdt.base = (void *)params->gdt_table;
1845 env->gdt.limit = sizeof(params->gdt_table) - 1;
1847 cpu_x86_load_seg(env, R_CS, KERNEL_CS);
1848 cpu_x86_load_seg(env, R_DS, KERNEL_DS);
1849 cpu_x86_load_seg(env, R_ES, KERNEL_DS);
1850 cpu_x86_load_seg(env, R_SS, KERNEL_DS);
1851 cpu_x86_load_seg(env, R_FS, KERNEL_DS);
1852 cpu_x86_load_seg(env, R_GS, KERNEL_DS);
1854 env->eip = KERNEL_LOAD_ADDR;
1855 env->regs[R_ESI] = KERNEL_PARAMS_ADDR;
1858 itv.it_interval.tv_sec = 0;
1859 itv.it_interval.tv_usec = 10 * 1000;
1860 itv.it_value.tv_sec = 0;
1861 itv.it_value.tv_usec = 10 * 1000;
1862 setitimer(ITIMER_REAL, &itv, NULL);
1865 struct pollfd ufds[2], *pf, *serial_ufd, *net_ufd;
1866 int ret, n, timeout;
1869 ret = cpu_x86_exec(env);
1871 /* if hlt instruction, we wait until the next IRQ */
1872 if (ret == EXCP_HLT)
1876 /* poll any events */
1880 if (!(serial_ports[0].lsr & UART_LSR_DR)) {
1883 pf->events = POLLIN;
1886 if (net_fd > 0 && ne2000_can_receive(&ne2000_state)) {
1889 pf->events = POLLIN;
1892 ret = poll(ufds, pf - ufds, timeout);
1894 if (serial_ufd && (serial_ufd->revents & POLLIN)) {
1895 n = read(0, &ch, 1);
1897 serial_received_byte(&serial_ports[0], ch);
1900 if (net_ufd && (net_ufd->revents & POLLIN)) {
1901 uint8_t buf[MAX_ETH_FRAME_SIZE];
1903 n = read(net_fd, buf, MAX_ETH_FRAME_SIZE);
1906 memset(buf + n, 0, 60 - n);
1909 ne2000_receive(&ne2000_state, buf, n);
1915 if (timer_irq_pending) {
1918 timer_irq_pending = 0;