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qstrdefsport.h
vm.c 11.85 KiB
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include "nlr.h"
#include "misc.h"
#include "mpyconfig.h"
#include "runtime.h"
#include "bc.h"
#define DECODE_UINT do { unum = *ip++; if (unum > 127) { unum = ((unum & 0x3f) << 8) | (*ip++); } } while (0)
#define DECODE_QSTR do { qstr = *ip++; if (qstr > 127) { qstr = ((qstr & 0x3f) << 8) | (*ip++); } } while (0)
#define PUSH(val) *--sp = (val)
#define POP() (*sp++)
// args are in reverse order in array
py_obj_t py_execute_byte_code(const byte *code, uint len, const py_obj_t *args, uint n_args) {
// careful: be sure to declare volatile any variables read in the exception handler (written is ok, I think)
const byte *ip = code;
py_obj_t stack[10];
py_obj_t *sp = &stack[10]; // stack grows down, sp points to top of stack
machine_uint_t unum;
machine_int_t snum;
qstr qstr;
py_obj_t obj1, obj2;
py_obj_t fast0 = NULL, fast1 = NULL, fast2 = NULL, fastn[4] = {NULL, NULL, NULL, NULL};
nlr_buf_t nlr;
// on the exception stack we store (ip, sp) for each block
machine_uint_t exc_stack[8];
machine_uint_t *volatile exc_sp = &exc_stack[-1]; // stack grows up, exc_sp points to top of stack
// init args
for (int i = 0; i < n_args; i++) {
if (i == 0) {
fast0 = args[n_args - 1];
} else if (i == 1) {
fast1 = args[n_args - 2];
} else if (i == 2) {
fast2 = args[n_args - 3];
} else {
assert(i - 3 < 4);
fastn[i - 3] = args[n_args - 1 - i];
}
}
// outer exception handling loop
for (;;) {
if (nlr_push(&nlr) == 0) {
// loop to execute byte code
for (;;) {
int op = *ip++;
switch (op) {
case PYBC_LOAD_CONST_FALSE:
PUSH(py_const_false);
break;
case PYBC_LOAD_CONST_NONE:
PUSH(py_const_none);
break;
case PYBC_LOAD_CONST_TRUE:
PUSH(py_const_true);
break;
case PYBC_LOAD_CONST_SMALL_INT:
snum = ip[0] | (ip[1] << 8); if (snum & 0x8000) {
snum |= ~0xffff;
}
ip += 2;
PUSH((py_obj_t)(snum << 1 | 1));
break;
case PYBC_LOAD_CONST_ID:
DECODE_QSTR;
PUSH(rt_load_const_str(qstr)); // TODO
break;
case PYBC_LOAD_CONST_STRING:
DECODE_QSTR;
PUSH(rt_load_const_str(qstr));
break;
case PYBC_LOAD_FAST_0:
PUSH(fast0);
break;
case PYBC_LOAD_FAST_1:
PUSH(fast1);
break;
case PYBC_LOAD_FAST_2:
PUSH(fast2);
break;
case PYBC_LOAD_FAST_N:
DECODE_UINT;
PUSH(fastn[unum - 3]);
break;
case PYBC_LOAD_NAME:
DECODE_QSTR;
PUSH(rt_load_name(qstr));
break;
case PYBC_LOAD_GLOBAL:
DECODE_QSTR;
PUSH(rt_load_global(qstr));
break;
case PYBC_LOAD_ATTR:
DECODE_QSTR;
*sp = rt_load_attr(*sp, qstr);
break;
case PYBC_LOAD_METHOD:
DECODE_QSTR;
sp -= 1;
rt_load_method(sp[1], qstr, sp);
break;
case PYBC_LOAD_BUILD_CLASS:
PUSH(rt_load_build_class());
break;
case PYBC_STORE_FAST_0:
fast0 = POP();
break;
case PYBC_STORE_FAST_1:
fast1 = POP();
break;
case PYBC_STORE_FAST_2:
fast2 = POP();
break;
case PYBC_STORE_FAST_N:
DECODE_UINT;
fastn[unum - 3] = POP();
break;
case PYBC_STORE_NAME:
DECODE_QSTR;
rt_store_name(qstr, POP());
break;
case PYBC_STORE_ATTR:
DECODE_QSTR;
rt_store_attr(sp[0], qstr, sp[1]);
sp += 2;
break;
case PYBC_STORE_SUBSCR:
rt_store_subscr(sp[1], sp[0], sp[2]);
sp += 3;
break;
case PYBC_DUP_TOP:
obj1 = *sp;
PUSH(obj1);
break;
case PYBC_DUP_TOP_TWO:
sp -= 2;
sp[0] = sp[2];
sp[1] = sp[3];
break;
case PYBC_POP_TOP:
++sp;
break;
case PYBC_ROT_THREE:
obj1 = sp[0];
sp[0] = sp[1];
sp[1] = sp[2];
sp[2] = obj1;
break;
case PYBC_JUMP:
DECODE_UINT;
ip = code + unum;
break;
case PYBC_POP_JUMP_IF_TRUE:
DECODE_UINT;
if (rt_is_true(POP())) {
ip = code + unum;
}
break;
case PYBC_POP_JUMP_IF_FALSE:
DECODE_UINT;
if (!rt_is_true(POP())) {
ip = code + unum;
}
break;
/* we are trying to get away without using this opcode
case PYBC_SETUP_LOOP:
DECODE_UINT;
// push_block(PYBC_SETUP_LOOP, code + unum, sp)
break;
*/
case PYBC_SETUP_EXCEPT:
DECODE_UINT;
*++exc_sp = (machine_uint_t)code + unum;
*++exc_sp = (machine_uint_t)sp;
break;
case PYBC_END_FINALLY:
// not implemented
// if TOS is an exception, reraises the exception (3 values on TOS)
// if TOS is an integer, does something else
// if TOS is None, just pops it and continues
// else error
assert(0);
break;
case PYBC_GET_ITER:
*sp = rt_getiter(*sp);
break;
case PYBC_FOR_ITER:
DECODE_UINT; // the jump offset if iteration finishes
obj1 = rt_iternext(*sp);
if (obj1 == py_const_stop_iteration) {
++sp; // pop the exhausted iterator
ip = code + unum; // jump to after for-block
} else {
PUSH(obj1); // push the next iteration value
}
break;
case PYBC_POP_BLOCK:
// pops block and restores the stack
assert(0);
break;
case PYBC_POP_EXCEPT:
// TODO need to work out how blocks work etc
// pops block, checks it's an exception block, and restores the stack, saving the 3 exception values to local threadstate
assert(exc_sp >= &exc_stack[0]);
//sp = (py_obj_t*)(*exc_sp--);
//exc_sp--; // discard ip
exc_sp -= 2;
//sp += 3; // pop 3 exception values
assert(sp <= &stack[10]);
break;
case PYBC_BINARY_OP:
unum = *ip++;
obj2 = POP();
obj1 = *sp;
*sp = rt_binary_op(unum, obj1, obj2);
break;
case PYBC_COMPARE_OP:
unum = *ip++;
obj2 = POP();
obj1 = *sp;
*sp = rt_compare_op(unum, obj1, obj2);
break;
case PYBC_BUILD_LIST:
DECODE_UINT;
obj1 = rt_build_list(unum, sp);
sp += unum - 1;
*sp = obj1;
break;
case PYBC_BUILD_MAP:
DECODE_UINT;
PUSH(rt_build_map(unum)); break;
case PYBC_STORE_MAP:
sp += 2;
rt_store_map(sp[0], sp[-2], sp[-1]);
break;
case PYBC_BUILD_SET:
DECODE_UINT;
obj1 = rt_build_set(unum, sp);
sp += unum - 1;
*sp = obj1;
break;
case PYBC_MAKE_FUNCTION:
DECODE_UINT;
PUSH(rt_make_function_from_id(unum));
break;
case PYBC_CALL_FUNCTION:
DECODE_UINT;
assert((unum & 0xff00) == 0); // n_keyword
unum &= 0xff; // n_positional
sp += unum;
*sp = rt_call_function_n(*sp, unum, sp - unum);
break;
case PYBC_CALL_METHOD:
DECODE_UINT;
assert((unum & 0xff00) == 0); // n_keyword
unum &= 0xff;
obj1 = rt_call_method_n(unum, sp);
sp += unum + 1;
*sp = obj1;
break;
case PYBC_RETURN_VALUE:
nlr_pop();
assert(sp == &stack[9]);
assert(exc_sp == &exc_stack[-1]);
return *sp;
default:
printf("code %p, offset %u, byte code 0x%02x not implemented\n", code, (uint)(ip - code), op);
assert(0);
nlr_pop();
return py_const_none;
}
}
} else {
// exception occurred
if (exc_sp >= &exc_stack[0]) {
// catch exception and pass to byte code
sp = (py_obj_t*)(exc_sp[0]);
ip = (const byte*)(exc_sp[-1]);
// push(traceback, exc-val, exc-type)
PUSH(py_const_none);
PUSH(nlr.ret_val);
PUSH(py_const_none);
} else {
// re-raise exception
nlr_jump(nlr.ret_val);
}
}
}
}