305 lines
6.8 KiB
C
305 lines
6.8 KiB
C
//*******************************************************************************/
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/* COS2000 - Compatible Operating System - LGPL v3 - Hordé Nicolas */
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/* */
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#include "types.h"
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#include "asm.h"
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#include "setup.h"
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#include "memory.h"
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extern hdr;
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/* paramètres de démarrage */
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static bootparams params;
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/* registre gdt */
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static struct gdtr gdtreg;
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/* table de GDT */
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static gdtdes gdt[GDT_SIZE];
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u8 kernel_version[] = "COS2000 Version " MACRO(VERSION) "- compiled " __DATE__ ;
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u8 initmemory(void)
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{
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u32 count = 0;
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miniregs reg;
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cleanreg(®);
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entrye820 *desc = params.e820_table;
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static struct entrye820 buf;
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do {
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reg.ax = 0xe820;
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reg.cx = sizeof(buf);
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reg.edx = SMAP;
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reg.di = &buf;
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interrupt(0x15, reg);
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if (reg.eflags & EFLAGS_CF)
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break;
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if (reg.eax != SMAP)
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{
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count = 0;
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break;
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}
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*desc++ = buf;
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count++;
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} while (reg.ebx && count < ARRAY_SIZE(params.e820_table));
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return params.e820_numbers= count;
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}
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void showstr(u8 *str)
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{
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while (*str!='\000')
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showchar(*str++);
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}
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void cleanreg(miniregs *reg)
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{
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for (u8 i;i<sizeof(miniregs);i++)
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*((u8 *)reg+i)=0;
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}
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void showchar(u8 achar)
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{
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miniregs reg;
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cleanreg(®);
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reg.bx = 0x0007;
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reg.cx = 0x0001;
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reg.ah = 0x0e;
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reg.al = achar;
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interrupt(0x10, reg); /* INT 10 - VIDEO - TELETYPE OUTPUT */
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}
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u8 gettime(void)
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{
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miniregs reg;
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cleanreg(®);
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reg.ah = 0x02;
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interrupt(0x1a, reg); /* TIME - GET REAL-TIME CLOCK TIME (AT,XT286,PS) */
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return reg.dh;
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}
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u8 waitchar(void)
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{
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miniregs reg;
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cleanreg(®);
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reg.ah = 0x00;
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interrupt(0x16, reg); /* INT 16 - KEYBOARD - GET KEYSTROKE */
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return reg.al;
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}
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void initkeyboard(void)
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{
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miniregs reg;
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cleanreg(®);
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reg.ah = 0x02;
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interrupt(0x16, reg); /* INT 16 - KEYBOARD - GET SHIFT FLAGS */
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params.kbflag=reg.al;
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reg.ah = 0x03;
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reg.al = 0x05;
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reg.bx = 0x00;
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interrupt(0x16, reg); /* INT 16 - KEYBOARD - SET TYPEMATIC RATE AND DELAY */
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}
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u8 empty8042(void)
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{
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u8 status;
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u32 loops = LOOPS_8042;
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u8 ffs = FF_8042;
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while (loops--) {
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iodelay();
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status = inb(0x64);
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if (status == 0xff) {
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if (!--ffs)
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return NULL;
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}
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if (status & 1) {
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iodelay();
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(void)inb(0x60);
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} else if (!(status & 2)) {
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return 1;
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}
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}
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return NULL;
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}
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void iodelay(void)
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{
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//asm("outb %%al,$0x80" ::);
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for(u32 loop=LOOPS_DELAY;loop>0;loop--) nop();
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}
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u8 testA20(void)
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{
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asm("xorw %%cx, %%cx\n\
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decw %%cx\n\
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movw %%cx, %%gs\n\
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movw $0x4000, %%cx\n\
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movw %%fs:(0x200), %%ax\n\
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pushw %%ax\n\
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1:\n\
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incw %%ax\n\
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movw %%ax, %%fs:(0x200)\n\
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call iodelay\n\
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cmpw %%gs:(0x210), %%ax\n\
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loope 1b\n\
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popw %%fs:(0x200)\n\
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xor %%ax,%%ax\n\
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je 2f\n\
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mov $0x1,%%ax\n\
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2:":::"ax","cx");
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}
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void enableA20kbc(void)
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{
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empty8042();
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outb(0xd1, 0x64);
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empty8042();
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outb(0xdf, 0x60);
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empty8042();
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outb(0xff, 0x64);
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empty8042();
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}
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void enableA20fast(void)
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{
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u8 port;
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port = inb(0x92);
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port |= 0x02;
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port &= ~0x01;
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outb(port, 0x92);
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}
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u8 enableA20(void)
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{
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int loops = LOOPS_A20_ENABLE;
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int kbcerr;
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while (loops--) {
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if (!testA20())
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return NULL;
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kbcerr = empty8042();
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if (!testA20())
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return NULL;
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if (!kbcerr) {
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enableA20kbc();
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if (!testA20())
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return NULL;
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}
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enableA20fast();
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if (!testA20())
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return NULL;
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}
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return 1;
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}
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/*******************************************************************************/
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/* Copie une portion de mémoire vers une autre */
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void memcpyto(void *src, void *dst, u32 count)
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{
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asm("push %%es\n\
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cld\n\
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xor %%eax,%%eax\n\
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mov %%ax,%%es\n\
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rep movsb\n\
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pop %%es"::"S" (src), "D" (dst), "c" (count):);
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}
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/*******************************************************************************/
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/* Créé un descripteur GDT */
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void makegdtdes(u32 base, u32 limite, u8 acces, u8 flags, gdtdes * desc)
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{
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desc->lim0_15 = (limite & 0xffff);
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desc->base0_15 = (base & 0xffff);
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desc->base16_23 = (base & 0xff0000) >> 16;
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desc->acces = acces;
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desc->lim16_19 = (limite & 0xf0000) >> 16;
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desc->flags = (flags & 0xf);
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desc->base24_31 = (base & 0xff000000) >> 24;
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return;
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}
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/*******************************************************************************/
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/* Initialise la GDT */
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void initgdt()
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{
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makegdtdes(0x0, 0x00000, 0x00, 0x00, &gdt[0]); /* descripteur nul */
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makegdtdes(0x0, 0xFFFFF, SEG_PRESENT | SEG_NORMAL | SEG_CODE | SEG_RING0 | SEG_READ | SEG_ACCESSED, GRANULARITY_4K | OPSIZE_32B | SYS_AVAILABLE, &gdt[1]); /* code -> SEL_KERNEL_CODE */
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makegdtdes(0x0, 0x00000, SEG_PRESENT | SEG_NORMAL | SEG_DATA | SEG_RING0 | SEG_EXPAND_DOWN | SEG_READ_WRITE | SEG_ACCESSED, GRANULARITY_4K | OPSIZE_32B | SYS_AVAILABLE, &gdt[2]); /* pile -> SEL_KERNEL_STACK */
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makegdtdes(0x0, 0x00000, 0x00, 0x00, &gdt[3]); /* LIBRE */
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makegdtdes(0x0, 0x00000, 0x00, 0x00, &gdt[4]); /* LIBRE */
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makegdtdes(0x0, 0xFFFFF, SEG_PRESENT | SEG_NORMAL | SEG_DATA | SEG_RING0 | SEG_READ_WRITE | SEG_ACCESSED, GRANULARITY_4K | OPSIZE_32B | SYS_AVAILABLE, &gdt[5]); /* data -> SEL_KERNEL_DATA */
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makegdtdes(0x0, 0x00000, 0x00, 0x00, &gdt[6]); /* LIBRE */
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makegdtdes(0x0, 0x00000, 0x00, 0x00, &gdt[7]); /* LIBRE */
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/* initialise le registre gdt */
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gdtreg.limite = GDT_SIZE * sizeof(gdtdes);
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gdtreg.base = GDT_ADDR;
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/* recopie de la GDT a son adresse */
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memcpyto(&gdt, (u8 *) gdtreg.base, gdtreg.limite);
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/* chargement du registre GDT */
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lgdt(gdtreg);
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}
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void maskinterrupts(void)
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{
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cli();
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outb(0x80, 0x70); /* Disable NMI */
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iodelay();
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outb(0xff, 0xa1); /* Mask all interrupts on the secondary PIC */
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iodelay();
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outb(0xfb, 0x21); /* Mask all but cascade on the primary PIC */
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iodelay();
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}
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void initcoprocessor(void)
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{
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outb(0, 0xf0);
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iodelay();
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outb(0, 0xf1);
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iodelay();
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}
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void initpmode()
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{
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if (enableA20()) {
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showstr("impossible d'ouvrir la ligne A20...\n");
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halt();
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}
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maskinterrupts();
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initgdt();
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gotopmode();
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}
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void initparams()
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{
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params.cmdline=((header*)&hdr)->cmd_line_ptr;
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params.ramdiskaddr=((header*)&hdr)->ramdisk_image;
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params.ramdisksize=((header*)&hdr)->ramdisk_size;
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asm("xorl %%eax,%%eax\n \
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movw %%ds,%%ax\n \
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shl $4,%%eax\n \
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addw %[bootparams],%%ax \n \
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movl %%eax,%%cr3"::[bootparams] "i" (¶ms));
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}
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void initvideo()
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{
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}
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void main(void)
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{
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showstr("*** Chargement de COS2000 - mode reel ***\r\n");
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initparams();
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showstr(" -Initialisation de la memoire\r\n");
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initmemory();
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showstr(" -Initialisation du clavier\r\n");
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initkeyboard();
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showstr(" -Initialisation du coprocesseur\r\n");
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initcoprocessor();
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showstr(" -Initialisation video & passage en mode protege\r\n");
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initvideo();
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initpmode();
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}
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