#include #include #include "opcodes.h" #define STACK_SZ 1024 #define CALLSTACK_SZ 64 #define MAX_VARS 65536 static imm_t callstack[CALLSTACK_SZ]; static unsigned callstack_pointer; static imm_t stack[STACK_SZ]; static unsigned stack_pointer; static jmp_buf exit_point; struct var_t { enum { TYPE_PLAIN, TYPE_SPECIAL } type; union { vartype val; struct { enum special_id special; }; }; bool constant; }; static struct var_t vars[MAX_VARS]; static int file_des; static unsigned current_line, num_lines; static off_t *line_offset; static bool want_quit; static int repeats_left; static imm_t repeat_line; static void vid_write(const char *str); instr_t read_instr(void) { instr_t ret; if(read(file_des, &ret, sizeof(ret)) != sizeof(ret)) want_quit = true; return ret; } imm_t read_imm(void) { imm_t ret; if(read(file_des, &ret, sizeof(ret)) != sizeof(ret)) want_quit = true; return ret; } imm_t read_varid(void) { varid_t ret; if(read(file_des, &ret, sizeof(ret)) != sizeof(ret)) want_quit = true; return ret; } imm_t read_byte(void) { unsigned char ret; if(read(file_des, &ret, sizeof(ret)) != sizeof(ret)) want_quit = true; return ret; } static void vid_write(const char *str) { printf("%s", str); } static void __attribute__((format(printf,1,2))) vid_writef(const char *fmt, ...) { char fmtbuf[256]; va_list ap; va_start(ap, fmt); vsnprintf(fmtbuf, sizeof(fmtbuf), fmt, ap); vid_write(fmtbuf); va_end(ap); } static void __attribute__((format(printf,1,2))) warning(const char *fmt, ...) { char fmtbuf[256]; va_list ap; va_start(ap, fmt); vsnprintf(fmtbuf, sizeof(fmtbuf), fmt, ap); vid_writef("Line %d: WARNING: %s\n", current_line, fmtbuf); va_end(ap); } static void init_globals(void) { current_line = 0; stack_pointer = 0; callstack_pointer = 0; want_quit = false; repeats_left = 0; repeat_line = 0; } static inline void push(imm_t n) { if(stack_pointer < STACK_SZ) stack[stack_pointer++] = n; else ERROR("stack overflow"); } static inline imm_t pop(void) { if(stack_pointer > 0) return stack[--stack_pointer]; else ERROR("stack underflow"); } static inline vartype getvar(varid_t varid) { if(varid < ARRAYLEN(vars)) { struct var_t *var = vars+varid; if(var->type == TYPE_PLAIN) return vars[varid].val; else return get_special(vars[varid].special); } } static inline void setvar(varid_t varid, vartype val) { if(varid < ARRAYLEN(vars) && !vars[varid].constant) vars[varid].val = val; else ERROR("cannot modify variable"); } static inline void mkconst(varid_t varid) { if(varid < ARRAYLEN(vars)) vars[varid].constant = true; } static inline void jump(imm_t line) { if(1 <= line && line <= num_lines) { lseek(file_des, line_offset[line], SEEK_SET); current_line = line; } else ERROR("jump target out of bounds"); } static void pushimm_handler(void) { push(read_imm()); } static void pushvar_handler(void) { push(getvar(read_varid())); } static void pop_handler(void) { setvar(read_varid(), pop()); } static void mkconst_handler(void) { mkconst(read_varid()); } static void incvar_handler(void) { varid_t varid = read_varid(); if(varid < ARRAYLEN(vars)) ++vars[varid].val; } static void decvar_handler(void) { varid_t varid = read_varid(); if(varid < ARRAYLEN(vars)) --vars[varid].val; } static void writestr_handler(void) { while(1) { char c = read_byte(); if(c) vid_writef("%c", c); else break; } } static void repeat_handler(void) { if(repeats_left > 0) { if(repeat_line + 1 != current_line) ERROR("nested REPEAT"); --repeats_left; if(repeats_left > 0) { jump(repeat_line); } } else { repeat_line = pop(); repeats_left = pop() - 1; jump(repeat_line); } } static void jump_handler(void) { jump(pop()); } static void subcall_handler(void) { if(callstack_pointer < CALLSTACK_SZ) { callstack[callstack_pointer++] = current_line + 1; jump(pop()); } else ERROR("call stack overflow"); } static void subret_handler(void) { if(callstack_pointer > 0) { jump(callstack[--callstack_pointer]); } else ERROR("call stack underflow"); } static void if_handler(void) { imm_t line = pop(); if(!pop()) jump(line); } static void delay_handler(void) { imm_t ms = pop(); struct timespec t; t.tv_sec = ms / 1000; t.tv_nsec = (ms % 1000) * 1000000; nanosleep(&t, NULL); } static void logvar_handler(void) { vid_writef(VARFORMAT, pop()); } static void quit_handler(void) { want_quit = true; } static void logascii_handler(void) { vid_writef("%c", pop()); } static void neg_handler(void) { stack[stack_pointer - 1] = -stack[stack_pointer - 1]; } static vartype eval_exp(vartype a1, vartype a2) { return a2<0 ? 0 : (a2==0?1:a1*eval_exp(a1, a2-1)); } static void pow_handler(void) { imm_t pow = pop(); imm_t base = pop(); push(eval_exp(base, pow)); } static void mul_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a*b); } static void div_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a/b); } static void mod_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a%b); } static void add_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a+b); } static void sub_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a-b); } static void eq_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a==b); } static void neq_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a!=b); } static void leq_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a<=b); } static void geq_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a>=b); } static void lt_handler(void) { imm_t b = pop(); imm_t a = pop(); push(ab); } static void lognot_handler(void) { push(!pop()); } static void logand_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a&&b); } static void logor_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a||b); } static void bitand_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a&b); } static void bitor_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a|b); } static void bitxor_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a^b); } static void bitcomp_handler(void) { push(~pop()); } static void lsh_handler(void) { imm_t b = pop(); imm_t a = pop(); push(a<>b); } static void sqrt_handler(void) { push(sqrt(pop())); } static void decl_const(void) { /* no checking, only the compiler can output this instruction */ varid_t varid = read_varid(); vars[varid].val = read_imm(); vars[varid].constant = true; } static void newline_handler(void) { vid_writef("\n"); } static void input_handler(void) { vartype val; scanf(VARFORMAT, &val); setvar(read_varid(), val); } static void mkspecial_handler(void) { varid_t varid = read_varid(); vars[varid].constant = true; vars[varid].type = TYPE_SPECIAL; vars[varid].special = read_imm(); } static void inc_line_pointer(void) { ++current_line; vars[0].val = current_line; } static void (*instr_tab[0x100])(void) = { pushimm_handler, /* 0x0 */ pushvar_handler, /* 0x1 */ pop_handler, /* 0x2 */ mkconst_handler, /* 0x3 */ incvar_handler, /* 0x4 */ decvar_handler, /* 0x5 */ writestr_handler, /* 0x6 */ repeat_handler, /* 0x7 */ jump_handler, /* 0x8 */ subcall_handler, /* 0x9 */ subret_handler, /* 0xa */ if_handler, /* 0xb */ delay_handler, /* 0xc */ logvar_handler, /* 0xd */ quit_handler, /* 0xe */ logascii_handler, /* 0xf */ neg_handler, /* 0x10 */ pow_handler, /* 0x11 */ mul_handler, /* 0x12 */ div_handler, /* 0x13 */ mod_handler, /* 0x14 */ add_handler, /* 0x15 */ sub_handler, /* 0x16 */ eq_handler, /* 0x17 */ neq_handler, /* 0x18 */ leq_handler, /* 0x19 */ geq_handler, /* 0x1a */ lt_handler, /* 0x1b */ gt_handler, /* 0x1c */ lognot_handler, /* 0x1d */ logand_handler, /* 0x1e */ logor_handler, /* 0x1f */ bitand_handler, /* 0x20 */ bitor_handler, /* 0x21 */ bitxor_handler, /* 0x22 */ bitcomp_handler, /* 0x23 */ lsh_handler, /* 0x24 */ rsh_handler, /* 0x25 */ sqrt_handler, /* 0x26 */ decl_const, /* 0x27 */ NULL, /* 0x28 */ NULL, /* 0x29 */ NULL, /* 0x2a */ NULL, /* 0x2b */ NULL, /* 0x2c */ NULL, /* 0x2d */ newline_handler, /* 0x2e */ input_handler, /* 0x2f */ mkspecial_handler, /* 0x30 */ NULL, /* 0x31 */ NULL, /* 0x32 */ NULL, /* 0x33 */ NULL, /* 0x34 */ NULL, /* 0x35 */ NULL, /* 0x36 */ NULL, /* 0x37 */ NULL, /* 0x38 */ NULL, /* 0x39 */ NULL, /* 0x3a */ NULL, /* 0x3b */ NULL, /* 0x3c */ NULL, /* 0x3d */ NULL, /* 0x3e */ NULL, /* 0x3f */ NULL, /* 0x40 */ NULL, /* 0x41 */ NULL, /* 0x42 */ NULL, /* 0x43 */ NULL, /* 0x44 */ NULL, /* 0x45 */ NULL, /* 0x46 */ NULL, /* 0x47 */ NULL, /* 0x48 */ NULL, /* 0x49 */ NULL, /* 0x4a */ NULL, /* 0x4b */ NULL, /* 0x4c */ NULL, /* 0x4d */ NULL, /* 0x4e */ NULL, /* 0x4f */ NULL, /* 0x50 */ NULL, /* 0x51 */ NULL, /* 0x52 */ NULL, /* 0x53 */ NULL, /* 0x54 */ NULL, /* 0x55 */ NULL, /* 0x56 */ NULL, /* 0x57 */ NULL, /* 0x58 */ NULL, /* 0x59 */ NULL, /* 0x5a */ NULL, /* 0x5b */ NULL, /* 0x5c */ NULL, /* 0x5d */ NULL, /* 0x5e */ NULL, /* 0x5f */ NULL, /* 0x60 */ NULL, /* 0x61 */ NULL, /* 0x62 */ NULL, /* 0x63 */ NULL, /* 0x64 */ NULL, /* 0x65 */ NULL, /* 0x66 */ NULL, /* 0x67 */ NULL, /* 0x68 */ NULL, /* 0x69 */ NULL, /* 0x6a */ NULL, /* 0x6b */ NULL, /* 0x6c */ NULL, /* 0x6d */ NULL, /* 0x6e */ NULL, /* 0x6f */ NULL, /* 0x70 */ NULL, /* 0x71 */ NULL, /* 0x72 */ NULL, /* 0x73 */ NULL, /* 0x74 */ NULL, /* 0x75 */ NULL, /* 0x76 */ NULL, /* 0x77 */ NULL, /* 0x78 */ NULL, /* 0x79 */ NULL, /* 0x7a */ NULL, /* 0x7b */ NULL, /* 0x7c */ NULL, /* 0x7d */ NULL, /* 0x7e */ NULL, /* 0x7f */ NULL, /* 0x80 */ NULL, /* 0x81 */ NULL, /* 0x82 */ NULL, /* 0x83 */ NULL, /* 0x84 */ NULL, /* 0x85 */ NULL, /* 0x86 */ NULL, /* 0x87 */ NULL, /* 0x88 */ NULL, /* 0x89 */ NULL, /* 0x8a */ NULL, /* 0x8b */ NULL, /* 0x8c */ NULL, /* 0x8d */ NULL, /* 0x8e */ NULL, /* 0x8f */ NULL, /* 0x90 */ NULL, /* 0x91 */ NULL, /* 0x92 */ NULL, /* 0x93 */ NULL, /* 0x94 */ NULL, /* 0x95 */ NULL, /* 0x96 */ NULL, /* 0x97 */ NULL, /* 0x98 */ NULL, /* 0x99 */ NULL, /* 0x9a */ NULL, /* 0x9b */ NULL, /* 0x9c */ NULL, /* 0x9d */ NULL, /* 0x9e */ NULL, /* 0x9f */ NULL, /* 0xa0 */ NULL, /* 0xa1 */ NULL, /* 0xa2 */ NULL, /* 0xa3 */ NULL, /* 0xa4 */ NULL, /* 0xa5 */ NULL, /* 0xa6 */ NULL, /* 0xa7 */ NULL, /* 0xa8 */ NULL, /* 0xa9 */ NULL, /* 0xaa */ NULL, /* 0xab */ NULL, /* 0xac */ NULL, /* 0xad */ NULL, /* 0xae */ NULL, /* 0xaf */ NULL, /* 0xb0 */ NULL, /* 0xb1 */ NULL, /* 0xb2 */ NULL, /* 0xb3 */ NULL, /* 0xb4 */ NULL, /* 0xb5 */ NULL, /* 0xb6 */ NULL, /* 0xb7 */ NULL, /* 0xb8 */ NULL, /* 0xb9 */ NULL, /* 0xba */ NULL, /* 0xbb */ NULL, /* 0xbc */ NULL, /* 0xbd */ NULL, /* 0xbe */ NULL, /* 0xbf */ NULL, /* 0xc0 */ NULL, /* 0xc1 */ NULL, /* 0xc2 */ NULL, /* 0xc3 */ NULL, /* 0xc4 */ NULL, /* 0xc5 */ NULL, /* 0xc6 */ NULL, /* 0xc7 */ NULL, /* 0xc8 */ NULL, /* 0xc9 */ NULL, /* 0xca */ NULL, /* 0xcb */ NULL, /* 0xcc */ NULL, /* 0xcd */ NULL, /* 0xce */ NULL, /* 0xcf */ NULL, /* 0xd0 */ NULL, /* 0xd1 */ NULL, /* 0xd2 */ NULL, /* 0xd3 */ NULL, /* 0xd4 */ NULL, /* 0xd5 */ NULL, /* 0xd6 */ NULL, /* 0xd7 */ NULL, /* 0xd8 */ NULL, /* 0xd9 */ NULL, /* 0xda */ NULL, /* 0xdb */ NULL, /* 0xdc */ NULL, /* 0xdd */ NULL, /* 0xde */ NULL, /* 0xdf */ NULL, /* 0xe0 */ NULL, /* 0xe1 */ NULL, /* 0xe2 */ NULL, /* 0xe3 */ NULL, /* 0xe4 */ NULL, /* 0xe5 */ NULL, /* 0xe6 */ NULL, /* 0xe7 */ NULL, /* 0xe8 */ NULL, /* 0xe9 */ NULL, /* 0xea */ NULL, /* 0xeb */ NULL, /* 0xec */ NULL, /* 0xed */ NULL, /* 0xee */ NULL, /* 0xef */ NULL, /* 0xf0 */ NULL, /* 0xf1 */ NULL, /* 0xf2 */ NULL, /* 0xf3 */ NULL, /* 0xf4 */ NULL, /* 0xf5 */ NULL, /* 0xf6 */ NULL, /* 0xf7 */ NULL, /* 0xf8 */ NULL, /* 0xf9 */ NULL, /* 0xfa */ NULL, /* 0xfb */ NULL, /* 0xfc */ NULL, /* 0xfd */ NULL, /* 0xfe */ inc_line_pointer, /* 0xff */ }; int ducky_vm(int fd) { if(!setjmp(exit_point)) { file_des = fd; init_globals(); if(read_imm() != DUCKY_MAGIC) ERROR("unknown format"); num_lines = read_imm(); line_offset = malloc(num_lines + 1); for(unsigned int i = 1; i <= num_lines; ++i) { line_offset[i] = read_imm(); } /* and... execute! */ while(!want_quit) { instr_t instr = read_instr(); if(want_quit) break; void (*handler)(void) = instr_tab[instr]; if(handler) handler(); else ERROR("invalid instruction"); } return 0; } else return 1; }