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/* Project:     OSLib

 * Description: The OS Construction Kit

 * Date:                1.6.2000

 * Idea by:             Luca Abeni & Gerardo Lamastra

 *

 * OSLib is an SO project aimed at developing a common, easy-to-use

 * low-level infrastructure for developing OS kernels and Embedded

 * Applications; it partially derives from the HARTIK project but it

 * currently is independently developed.

 *

 * OSLib is distributed under GPL License, and some of its code has

 * been derived from the Linux kernel source; also some important

 * ideas come from studying the DJGPP go32 extender.

 *

 * We acknowledge the Linux Community, Free Software Foundation,

 * D.J. Delorie and all the other developers who believe in the

 * freedom of software and ideas.

 *

 * For legalese, check out the included GPL license.

 */

/*      VM86 demo: tries to call BIOS services in vm86 mode... */

#include <ll/i386/hw-func.h>

#include <ll/i386/tss-ctx.h>

#include <ll/i386/x-bios.h>

#include <ll/i386/cons.h>

#include <ll/i386/error.h>

#include <ll/stdlib.h>

#define T  1000

#if 1

#define WAIT()  for (w = 0; w < 0xFFFFFFFF; w++)

#else

#define WAIT()  for (w = 0; w < 0xFFFFF; w++)

#endif

static unsigned long int w;

#define __VM86__

#ifdef __VM86__

//void emulate(void)

void emulate(DWORD intnum, struct registers r)

{

    TSS *vm86_tss;

    DWORD *bos;

    DWORD isr_cs, isr_eip;

    WORD *old_esp;

    DWORD *IRQTable_entry;

    CONTEXT c = get_TR();

    vm86_tss = vm86_get_tss();

    bos = (DWORD *)vm86_tss->esp0;

    if (c == X_VM86_TSS) {

            /*

        message("Entering ESP: %lx (= 0x%lx?)\n",

                (DWORD)(tos + 9), vm86_tss->esp0);

        message("Old EIP: 0x%lx    0x%lx\n", *(tos + 9), *(bos - 9));

        message("Old CS: 0x%x    0x%x\n", (WORD)(*(tos + 10)), (WORD)*(bos - 8));

        message("Old EFlags: 0x%lx    0x%lx\n", *(tos + 11), *(bos - 7));

        message("Old ESP: 0x%lx    0x%lx\n", *(tos + 12), *(bos - 6));

        message("Emulate, please!!!\n");

*/     

        old_esp = (WORD *)(*(bos - 6) + (*(bos - 5) << 4));

//      *(old_esp - 1) = /*(WORD)(*(bos - 7))*/ CPU_FLAG_VM | CPU_FLAG_IOPL;

        r.flags = CPU_FLAG_VM | CPU_FLAG_IOPL;

        *(old_esp - 2) = (WORD)(*(bos - 8));

        *(old_esp - 3) = (WORD)(*(bos - 9));

        *(bos - 6) -= 6;

        /* We are emulating INT 0x6d */

        IRQTable_entry = (void *)(0L);

        isr_cs= ((IRQTable_entry[0x6d]) & 0xFFFF0000) >> 16;

        isr_eip = ((IRQTable_entry[0x6d]) & 0x0000FFFF);

        /*

        message("I have to call 0x%lx:0x%lx\n", isr_cs, isr_eip);

        */

        *(bos - 8) = isr_cs;

        *(bos - 9) = isr_eip;

    }

}

void vm86BIOSDemo(void)

{

    X_REGS16 ir,or;

    X_SREGS16 sr;

    /* Print ASCII character */

    ir.h.ah = 9;

    /* AL = character to display */

    ir.h.al = '+';

    /* BH = page number, BL = attribute */

    ir.x.bx = 3;

    /* Count number */

    ir.x.cx = 3;

    vm86_callBIOS(0x10,&ir,&or,&sr);

}

#else

void XBIOSDemo(void)

{

    X_REGS16 ir,or;

    X_SREGS16 sr;

    /* Set video mode */

    ir.h.ah = 9;

    ir.h.al = '+';

    ir.x.bx = 3;

    ir.x.cx = 3;

    X_callBIOS(0x10,&ir,&or,&sr);

}                                                                            

#endif

void BIOSDemo(void)

{

    X_REGS16 ir,or;

    X_SREGS16 sr;

    register int i;

    /* Set video mode */

    ir.h.ah = 0;

#if 0

    ir.h.al = 0x03;

    vm86_callBIOS(0x10,&ir,&or,&sr);

        ir.h.ah = 0x0C;

        ir.h.al = i % 16;

        ir.x.bx = 0;

        ir.x.dx = i+40;

        ir.x.cx = i+100;

        vm86_callBIOS(0x10,&ir,&or,&sr);

#else

    ir.h.al = 0x12;

    vm86_callBIOS(0x10,&ir,&or,&sr);

    /* Put some pixels */

    for (i = 0; i < 200; i++) {

        ir.h.ah = 0x0C;

        ir.h.al = i % 16;

        ir.x.bx = 0;

        ir.x.dx = i+40;

        ir.x.cx = i+100;

        vm86_callBIOS(0x10,&ir,&or,&sr);

    }

#endif

    WAIT();

    /* Set video mode */

    ir.h.ah = 0;

    ir.h.al = 0x03;    

    vm86_callBIOS(0x10,&ir,&or,&sr);

}

int main (int argc, char *argv[])

{

    DWORD sp1, sp2;

    WORD c;

    int i;

    struct multiboot_info *mbi;

    sp1 = get_SP();

    mbi = l1_init();

    if (mbi == NULL) {

            message("Error in LowLevel initialization code...\n");

            l1_exit(-1);

    }

    message("Starting...");

    c = ll_context_save();

    message("CX=%x\n",c);

    for (i = 0; i < 0x4F000; i++);

#ifdef __VM86__

    vm86_init();

    l1_int_bind(0x6d, emulate);

    /*

    l1_irq_bind(0x6d, emulate);

    */

    BIOSDemo();

#else

    XBIOSDemo();

#endif

    sp2 = get_SP();

    message("End reached!\n");

    message("Actual stack : %lx - ", sp2);

    message("Begin stack : %lx\n", sp1);

    message("Check if same : %s\n",sp1 == sp2 ? "Ok :-)" : "No :-(");

    l1_end();

    return 1;

}