2 * Example of use of user mode libqemu: launch a basic .com DOS
19 int cpu_get_pic_interrupt(CPUState *env)
24 uint64_t cpu_get_tsc(CPUState *env)
29 static void set_gate(void *ptr, unsigned int type, unsigned int dpl,
30 unsigned long addr, unsigned int sel)
33 e1 = (addr & 0xffff) | (sel << 16);
34 e2 = (addr & 0xffff0000) | 0x8000 | (dpl << 13) | (type << 8);
35 stl((uint8_t *)ptr, e1);
36 stl((uint8_t *)ptr + 4, e2);
39 uint64_t idt_table[256];
41 /* only dpl matters as we do only user space emulation */
42 static void set_idt(int n, unsigned int dpl)
44 set_gate(idt_table + n, 0, dpl, 0, 0);
47 void qemu_free(void *ptr)
52 void *qemu_malloc(size_t size)
57 void *qemu_mallocz(size_t size)
60 ptr = qemu_malloc(size);
67 void *qemu_vmalloc(size_t size)
69 return memalign(4096, size);
72 void qemu_vfree(void *ptr)
77 void qemu_printf(const char *fmt, ...)
85 /* XXX: this is a bug in helper2.c */
88 /**********************************************/
90 #define COM_BASE_ADDR 0x10100
94 printf("qruncom version 0.1 (c) 2003 Fabrice Bellard\n"
95 "usage: qruncom file.com\n"
96 "user mode libqemu demo: run simple .com DOS executables\n");
100 static inline uint8_t *seg_to_linear(unsigned int seg, unsigned int reg)
102 return (uint8_t *)((seg << 4) + (reg & 0xffff));
105 static inline void pushw(CPUState *env, int val)
107 env->regs[R_ESP] = (env->regs[R_ESP] & ~0xffff) | ((env->regs[R_ESP] - 2) & 0xffff);
108 *(uint16_t *)seg_to_linear(env->segs[R_SS].selector, env->regs[R_ESP]) = val;
111 static void host_segv_handler(int host_signum, siginfo_t *info,
114 if (cpu_signal_handler(host_signum, info, puc)) {
120 int main(int argc, char **argv)
123 const char *filename;
131 vm86_mem = mmap((void *)0x00000000, 0x110000,
132 PROT_WRITE | PROT_READ | PROT_EXEC,
133 MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
134 if (vm86_mem == MAP_FAILED) {
139 /* load the MSDOS .com executable */
140 fd = open(filename, O_RDONLY);
145 ret = read(fd, vm86_mem + COM_BASE_ADDR, 65536 - 256);
152 /* install exception handler for CPU emulator */
154 struct sigaction act;
156 sigfillset(&act.sa_mask);
157 act.sa_flags = SA_SIGINFO;
158 // act.sa_flags |= SA_ONSTACK;
160 act.sa_sigaction = host_segv_handler;
161 sigaction(SIGSEGV, &act, NULL);
162 sigaction(SIGBUS, &act, NULL);
165 // cpu_set_log(CPU_LOG_TB_IN_ASM | CPU_LOG_TB_OUT_ASM | CPU_LOG_EXEC);
167 env = cpu_init("qemu32");
169 cpu_x86_set_cpl(env, 3);
171 env->cr[0] = CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK;
172 /* NOTE: hflags duplicates some of the virtual CPU state */
173 env->hflags |= HF_PE_MASK | VM_MASK;
175 /* flags setup : we activate the IRQs by default as in user
176 mode. We also activate the VM86 flag to run DOS code */
177 env->eflags |= IF_MASK | VM_MASK;
179 /* init basic registers */
181 env->regs[R_ESP] = 0xfffe;
182 seg = (COM_BASE_ADDR - 0x100) >> 4;
184 cpu_x86_load_seg_cache(env, R_CS, seg,
185 (seg << 4), 0xffff, 0);
186 cpu_x86_load_seg_cache(env, R_SS, seg,
187 (seg << 4), 0xffff, 0);
188 cpu_x86_load_seg_cache(env, R_DS, seg,
189 (seg << 4), 0xffff, 0);
190 cpu_x86_load_seg_cache(env, R_ES, seg,
191 (seg << 4), 0xffff, 0);
192 cpu_x86_load_seg_cache(env, R_FS, seg,
193 (seg << 4), 0xffff, 0);
194 cpu_x86_load_seg_cache(env, R_GS, seg,
195 (seg << 4), 0xffff, 0);
197 /* exception support */
198 env->idt.base = (unsigned long)idt_table;
199 env->idt.limit = sizeof(idt_table) - 1;
221 /* put return code */
222 *seg_to_linear(env->segs[R_CS].selector, 0) = 0xb4; /* mov ah, $0 */
223 *seg_to_linear(env->segs[R_CS].selector, 1) = 0x00;
224 *seg_to_linear(env->segs[R_CS].selector, 2) = 0xcd; /* int $0x21 */
225 *seg_to_linear(env->segs[R_CS].selector, 3) = 0x21;
228 /* the value of these registers seem to be assumed by pi_10.com */
229 env->regs[R_ESI] = 0x100;
230 env->regs[R_ECX] = 0xff;
231 env->regs[R_EBP] = 0x0900;
232 env->regs[R_EDI] = 0xfffe;
234 /* inform the emulator of the mmaped memory */
235 page_set_flags(0x00000000, 0x110000,
236 PAGE_WRITE | PAGE_READ | PAGE_EXEC | PAGE_VALID);
239 ret = cpu_x86_exec(env);
244 int_num = *(uint8_t *)(env->segs[R_CS].base + env->eip + 1);
247 ah = (env->regs[R_EAX] >> 8) & 0xff;
249 case 0x00: /* exit */
251 case 0x02: /* write char */
253 uint8_t c = env->regs[R_EDX];
257 case 0x09: /* write string */
261 c = *seg_to_linear(env->segs[R_DS].selector, env->regs[R_EAX]);
266 env->regs[R_EAX] = (env->regs[R_EAX] & ~0xff) | '$';
271 fprintf(stderr, "unsupported int 0x%02x\n", int_num);
272 cpu_dump_state(env, stderr, fprintf, 0);
279 fprintf(stderr, "unhandled cpu_exec return code (0x%x)\n", ret);
280 cpu_dump_state(env, stderr, fprintf, 0);