--- /dev/null
+/*
+ * Example of use of user mode libqemu: 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 "cpu.h"
+
+//#define SIGTEST
+
+CPUState *cpu_single_env = NULL;
+
+void cpu_outb(CPUState *env, int addr, int val)
+{
+ fprintf(stderr, "outb: port=0x%04x, data=%02x\n", addr, val);
+}
+
+void cpu_outw(CPUState *env, int addr, int val)
+{
+ fprintf(stderr, "outw: port=0x%04x, data=%04x\n", addr, val);
+}
+
+void cpu_outl(CPUState *env, int addr, int val)
+{
+ fprintf(stderr, "outl: port=0x%04x, data=%08x\n", addr, val);
+}
+
+int cpu_inb(CPUState *env, int addr)
+{
+ fprintf(stderr, "inb: port=0x%04x\n", addr);
+ return 0;
+}
+
+int cpu_inw(CPUState *env, int addr)
+{
+ fprintf(stderr, "inw: port=0x%04x\n", addr);
+ return 0;
+}
+
+int cpu_inl(CPUState *env, int addr)
+{
+ fprintf(stderr, "inl: port=0x%04x\n", addr);
+ return 0;
+}
+
+int cpu_get_pic_interrupt(CPUState *env)
+{
+ return -1;
+}
+
+static void set_gate(void *ptr, unsigned int type, unsigned int dpl,
+ unsigned long addr, unsigned int sel)
+{
+ unsigned int e1, e2;
+ e1 = (addr & 0xffff) | (sel << 16);
+ e2 = (addr & 0xffff0000) | 0x8000 | (dpl << 13) | (type << 8);
+ stl((uint8_t *)ptr, e1);
+ stl((uint8_t *)ptr + 4, e2);
+}
+
+uint64_t idt_table[256];
+
+/* only dpl matters as we do only user space emulation */
+static void set_idt(int n, unsigned int dpl)
+{
+ set_gate(idt_table + n, 0, dpl, 0, 0);
+}
+
+void qemu_free(void *ptr)
+{
+ free(ptr);
+}
+
+void *qemu_malloc(size_t size)
+{
+ return malloc(size);
+}
+
+void qemu_printf(const char *fmt, ...)
+{
+ va_list ap;
+ va_start(ap, fmt);
+ vprintf(fmt, ap);
+ va_end(ap);
+}
+
+/* XXX: this is a bug in helper2.c */
+int errno;
+
+/**********************************************/
+
+#define COM_BASE_ADDR 0x10100
+
+void usage(void)
+{
+ printf("qruncom version 0.1 (c) 2003 Fabrice Bellard\n"
+ "usage: qruncom file.com\n"
+ "user mode libqemu demo: run simple .com DOS executables\n");
+ exit(1);
+}
+
+static inline uint8_t *seg_to_linear(unsigned int seg, unsigned int reg)
+{
+ return (uint8_t *)((seg << 4) + (reg & 0xffff));
+}
+
+static inline void pushw(CPUState *env, int val)
+{
+ env->regs[R_ESP] = (env->regs[R_ESP] & ~0xffff) | ((env->regs[R_ESP] - 2) & 0xffff);
+ *(uint16_t *)seg_to_linear(env->segs[R_SS].selector, env->regs[R_ESP]) = val;
+}
+
+static void host_segv_handler(int host_signum, siginfo_t *info,
+ void *puc)
+{
+ if (cpu_signal_handler(host_signum, info, puc)) {
+ return;
+ }
+ abort();
+}
+
+int main(int argc, char **argv)
+{
+ uint8_t *vm86_mem;
+ const char *filename;
+ int fd, ret, seg;
+ CPUState *env;
+
+ 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);
+ }
+
+ /* 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);
+
+ /* install exception handler for CPU emulator */
+ {
+ struct sigaction act;
+
+ sigfillset(&act.sa_mask);
+ act.sa_flags = SA_SIGINFO;
+ // act.sa_flags |= SA_ONSTACK;
+
+ act.sa_sigaction = host_segv_handler;
+ sigaction(SIGSEGV, &act, NULL);
+ sigaction(SIGBUS, &act, NULL);
+#if defined (TARGET_I386) && defined(USE_CODE_COPY)
+ sigaction(SIGFPE, &act, NULL);
+#endif
+ }
+
+ // cpu_set_log(CPU_LOG_TB_IN_ASM | CPU_LOG_TB_OUT_ASM | CPU_LOG_EXEC);
+
+ env = cpu_init();
+
+ /* disable code copy to simplify debugging */
+ code_copy_enabled = 0;
+
+ /* set user mode state (XXX: should be done automatically by
+ cpu_init ?) */
+ env->user_mode_only = 1;
+
+ cpu_x86_set_cpl(env, 3);
+
+ env->cr[0] = CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK;
+ /* NOTE: hflags duplicates some of the virtual CPU state */
+ env->hflags |= HF_PE_MASK | VM_MASK;
+
+ /* flags setup : we activate the IRQs by default as in user
+ mode. We also activate the VM86 flag to run DOS code */
+ env->eflags |= IF_MASK | VM_MASK;
+
+ /* init basic registers */
+ env->eip = 0x100;
+ env->regs[R_ESP] = 0xfffe;
+ seg = (COM_BASE_ADDR - 0x100) >> 4;
+
+ cpu_x86_load_seg_cache(env, R_CS, seg,
+ (uint8_t *)(seg << 4), 0xffff, 0);
+ cpu_x86_load_seg_cache(env, R_SS, seg,
+ (uint8_t *)(seg << 4), 0xffff, 0);
+ cpu_x86_load_seg_cache(env, R_DS, seg,
+ (uint8_t *)(seg << 4), 0xffff, 0);
+ cpu_x86_load_seg_cache(env, R_ES, seg,
+ (uint8_t *)(seg << 4), 0xffff, 0);
+ cpu_x86_load_seg_cache(env, R_FS, seg,
+ (uint8_t *)(seg << 4), 0xffff, 0);
+ cpu_x86_load_seg_cache(env, R_GS, seg,
+ (uint8_t *)(seg << 4), 0xffff, 0);
+
+ /* exception support */
+ env->idt.base = (void *)idt_table;
+ env->idt.limit = sizeof(idt_table) - 1;
+ set_idt(0, 0);
+ set_idt(1, 0);
+ set_idt(2, 0);
+ set_idt(3, 3);
+ set_idt(4, 3);
+ set_idt(5, 3);
+ set_idt(6, 0);
+ set_idt(7, 0);
+ set_idt(8, 0);
+ set_idt(9, 0);
+ set_idt(10, 0);
+ set_idt(11, 0);
+ set_idt(12, 0);
+ set_idt(13, 0);
+ set_idt(14, 0);
+ set_idt(15, 0);
+ set_idt(16, 0);
+ set_idt(17, 0);
+ set_idt(18, 0);
+ set_idt(19, 0);
+
+ /* put return code */
+ *seg_to_linear(env->segs[R_CS].selector, 0) = 0xb4; /* mov ah, $0 */
+ *seg_to_linear(env->segs[R_CS].selector, 1) = 0x00;
+ *seg_to_linear(env->segs[R_CS].selector, 2) = 0xcd; /* int $0x21 */
+ *seg_to_linear(env->segs[R_CS].selector, 3) = 0x21;
+ pushw(env, 0x0000);
+
+ /* the value of these registers seem to be assumed by pi_10.com */
+ env->regs[R_ESI] = 0x100;
+ env->regs[R_ECX] = 0xff;
+ env->regs[R_EBP] = 0x0900;
+ env->regs[R_EDI] = 0xfffe;
+
+ /* inform the emulator of the mmaped memory */
+ page_set_flags(0x00000000, 0x110000,
+ PAGE_WRITE | PAGE_READ | PAGE_EXEC | PAGE_VALID);
+
+ for(;;) {
+ ret = cpu_x86_exec(env);
+ switch(ret) {
+ case EXCP0D_GPF:
+ {
+ int int_num, ah;
+ int_num = *(env->segs[R_CS].base + env->eip + 1);
+ if (int_num != 0x21)
+ goto unknown_int;
+ ah = (env->regs[R_EAX] >> 8) & 0xff;
+ switch(ah) {
+ case 0x00: /* exit */
+ exit(0);
+ case 0x02: /* write char */
+ {
+ uint8_t c = env->regs[R_EDX];
+ write(1, &c, 1);
+ }
+ break;
+ case 0x09: /* write string */
+ {
+ uint8_t c;
+ for(;;) {
+ c = *seg_to_linear(env->segs[R_DS].selector, env->regs[R_EAX]);
+ if (c == '$')
+ break;
+ write(1, &c, 1);
+ }
+ env->regs[R_EAX] = (env->regs[R_EAX] & ~0xff) | '$';
+ }
+ break;
+ default:
+ unknown_int:
+ fprintf(stderr, "unsupported int 0x%02x\n", int_num);
+ cpu_dump_state(env, stderr, 0);
+ // exit(1);
+ }
+ env->eip += 2;
+ }
+ break;
+ default:
+ fprintf(stderr, "unhandled cpu_exec return code (0x%x)\n", ret);
+ cpu_dump_state(env, stderr, 0);
+ exit(1);
+ }
+ }
+}
projects / qemu / commitdiff