Tryag File Manager

//proc/self/root/usr/share/doc/syslinux-4.02/sample/filetest.c

#include <com32.h>
#include <stdarg.h>

#define NULL ((void *)0)
int printf(const char *, ...);
int putchar(int);

static inline void memset(void *buf, int ch, unsigned int len)
{
    asm volatile ("cld; rep; stosb":"+D" (buf), "+c"(len):"a"(ch):"memory");
}

static void strcpy(char *dst, const char *src)
{
    while (*src)
	*dst++ = *src++;

*dst = '\0';
}

static void printregs(const com32sys_t * r)
{
    printf("eflags = %08x  ds = %04x  es = %04x  fs = %04x  gs = %04x\n"
	   "eax = %08x  ebx = %08x  ecx = %08x  edx = %08x\n"
	   "ebp = %08x  esi = %08x  edi = %08x  esp = %08x\n",
	   r->eflags.l, r->ds, r->es, r->fs, r->gs,
	   r->eax.l, r->ebx.l, r->ecx.l, r->edx.l,
	   r->ebp.l, r->esi.l, r->edi.l, r->_unused_esp.l);
}

int __start(void)
{
    unsigned int ax, cx, si, t;
    com32sys_t inreg, outreg;
    char *p;

/* Test null system call */
    inreg.eflags.l = 0xffffffff;
    inreg.eax.l = 0x11110000;
    inreg.ecx.l = 0x22222222;
    inreg.edx.l = 0x33333333;
    inreg.ebx.l = 0x44444444;
    inreg.ebp.l = 0x55555555;
    inreg.esi.l = 0x66666666;
    inreg.edi.l = 0x77777777;
    inreg.ds = 0xaaaa;
    inreg.es = 0xbbbb;
    inreg.fs = 0xcccc;
    inreg.gs = 0xdddd;
    printregs(&inreg);
    __com32.cs_intcall(0x22, &inreg, &outreg);
    printregs(&outreg);
    printf("----\n");

memset(&inreg, 0, sizeof inreg);
    memset(&outreg, 0, sizeof outreg);
    strcpy(__com32.cs_bounce, "test.txt");
    inreg.eax.w[0] = 0x0006;	// Open file
    inreg.esi.w[0] = OFFS(__com32.cs_bounce);
    inreg.es = SEG(__com32.cs_bounce);
    printregs(&inreg);
    __com32.cs_intcall(0x22, &inreg, &outreg);
    printregs(&outreg);
    printf("----\n");

si = outreg.esi.w[0];	/* File handle */
    cx = outreg.ecx.w[0];	/* Block size */
    ax = outreg.eax.l;		/* File length */

while (si) {
	/* We can only read 64K per call */
	t = (ax > 65536) ? 65536 / cx : (ax + cx - 1) / cx;

memset(&inreg, 0, sizeof inreg);
	inreg.esi.w[0] = si;
	inreg.ecx.w[0] = t;	/* Block count */
	inreg.eax.w[0] = 0x0007;	// Read file
	inreg.ebx.w[0] = OFFS(__com32.cs_bounce);
	inreg.es = SEG(__com32.cs_bounce);
	printregs(&inreg);
	__com32.cs_intcall(0x22, &inreg, &outreg);
	printregs(&outreg);
	printf("----\n");
	si = outreg.esi.w[0];

/* Print the buffer */
	t = (ax < 65536) ? ax : 65536;
	p = __com32.cs_bounce;
	while (t) {
	    putchar(*p++);
	    t--;
	    ax--;
	}
    }

return 0;
}