vswitchperf - **THIS REPO HAS BEEN ARCHIVED. SEE vineperf**

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Diffstat (limited to 'docs/release')

-rwxr-xr-x

1 files changed, 38 insertions, 0 deletions

/* * Simple example of use of vm86: launch a basic .com DOS executable */ #include <stdlib.h> #include <stdio.h> #include <string.h> #include <inttypes.h> #include <unistd.h> #include <fcntl.h> #include <sys/mman.h> #include <signal.h> #include <linux/unistd.h> #include <asm/vm86.h> extern int vm86 (unsigned long int subfunction, struct vm86plus_struct *info); #define VIF_MASK 0x00080000 //#define SIGTEST #define COM_BASE_ADDR 0x10100 static void usage(void) { printf("runcom version 0.1 (c) 2003 Fabrice Bellard\n" "usage: runcom file.com\n" "VM86 Run simple .com DOS executables (linux vm86 test mode)\n"); exit(1); } static inline void set_bit(uint8_t *a, unsigned int bit) { a[bit / 8] |= (1 << (bit % 8)); } static inline uint8_t *seg_to_linear(unsigned int seg, unsigned int reg) { return (uint8_t *)((seg << 4) + (reg & 0xffff)); } static inline void pushw(struct vm86_regs *r, int val) { r->esp = (r->esp & ~0xffff) | ((r->esp - 2) & 0xffff); *(uint16_t *)seg_to_linear(r->ss, r->esp) = val; } void dump_regs(struct vm86_regs *r) { fprintf(stderr, "EAX=%08lx EBX=%08lx ECX=%08lx EDX=%08lx\n" "ESI=%08lx EDI=%08lx EBP=%08lx ESP=%08lx\n" "EIP=%08lx EFL=%08lx\n" "CS=%04x DS=%04x ES=%04x SS=%04x FS=%04x GS=%04x\n", r->eax, r->ebx, r->ecx, r->edx, r->esi, r->edi, r->ebp, r->esp, r->eip, r->eflags, r->cs, r->ds, r->es, r->ss, r->fs, r->gs); } #ifdef SIGTEST void alarm_handler(int sig) { fprintf(stderr, "alarm signal=%d\n", sig); alarm(1); } #endif int main(int argc, char **argv) { uint8_t *vm86_mem; const char *filename; int fd, ret, seg; struct vm86plus_struct ctx; struct vm86_regs *r; if (argc != 2) usage(); filename = argv[1]; vm86_mem = mmap((void *)0x00000000, 0x110000, PROT_WRITE | PROT_READ | PROT_EXEC, MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0); if (vm86_mem == MAP_FAILED) { perror("mmap"); exit(1); } #ifdef SIGTEST { struct sigaction act; act.sa_handler = alarm_handler; sigemptyset(&act.sa_mask); act.sa_flags = 0; sigaction(SIGALRM, &act, NULL); alarm(1); } #endif /* load the MSDOS .com executable */ fd = open(filename, O_RDONLY); if (fd < 0) { perror(filename); exit(1); } ret = read(fd, vm86_mem + COM_BASE_ADDR, 65536 - 256); if (ret < 0) { perror("read"); exit(1); } close(fd); memset(&ctx, 0, sizeof(ctx)); /* init basic registers */ r = &ctx.regs; r->eip = 0x100; r->esp = 0xfffe; seg = (COM_BASE_ADDR - 0x100) >> 4; r->cs = seg; r->ss = seg; r->ds = seg; r->es = seg; r->fs = seg; r->gs = seg; r->eflags = VIF_MASK; /* put return code */ set_bit((uint8_t *)&ctx.int_revectored, 0x21); *seg_to_linear(r->cs, 0) = 0xb4; /* mov ah, $0 */ *seg_to_linear(r->cs, 1) = 0x00; *seg_to_linear(r->cs, 2) = 0xcd; /* int $0x21 */ *seg_to_linear(r->cs, 3) = 0x21; pushw(&ctx.regs, 0x0000); /* the value of these registers seem to be assumed by pi_10.com */ r->esi = 0x100; r->ecx = 0xff; r->ebp = 0x0900; r->edi = 0xfffe; for(;;) { ret = vm86(VM86_ENTER, &ctx); switch(VM86_TYPE(ret)) { case VM86_INTx: { int int_num, ah; int_num = VM86_ARG(ret); if (int_num != 0x21) goto unknown_int; ah = (r->eax >> 8) & 0xff; switch(ah) { case 0x00: /* exit */ exit(0); case 0x02: /* write char */ { uint8_t c = r->edx; write(1, &c, 1); } break; case 0x09: /* write string */ { uint8_t c; for(;;) { c = *seg_to_linear(r->ds, r->edx); if (c == '$') break; write(1, &c, 1); } r->eax = (r->eax & ~0xff) | '$'; } break; default: unknown_int: fprintf(stderr, "unsupported int 0x%02x\n", int_num); dump_regs(&ctx.regs); // exit(1); } } break; case VM86_SIGNAL: /* a signal came, we just ignore that */ break; case VM86_STI: break; default: fprintf(stderr, "unhandled vm86 return code (0x%x)\n", ret); dump_regs(&ctx.regs); exit(1); } } }


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