python bytecode instruction study

Question

I am written some programs containing loop function used the dis module to disassemble

import dis
def f():
    a = 10
    while a < 50:
         print a
         a+=1
    while a < 100:
         print a
         a+=1
dis.dis(f)

0 load_const  1 (10)
3 store_fast  0 (a)
6 setup_loop  31 (to 40)
9 load_fast   0 (a)
12 load_const  2(50)
15 compare_op  0(<)
18 pop_jump_if_false 39
21 laod_fast  0(a)
24 print_item 
25 print_newline
26 load_fast 0(a)
29 load_const 3(1)
32 inplace_add 
33store_fast  0(a)
36 jump_absolute 9
39 pop_block 
40 setup_loop  31 (to 74)
43 load_fast 0(a)
46 load_const 4(10)
49 compare_op 0 (<)
52 pop_jump_if_false 73
55 load_fast 0(a)
58 print_item
59 print_newline
60 load_fast 0 (a)
63 load_const 3(1)
66 inplace_add
67 store_fast 0(a)
70 jump_absolute 43
73 pop_block
74 load_const 0(none)
77 return_value

and i see some instruction like load_const, load_name etc.... but i didn't how actually SETUP_LOOP and Function call instructions..... please anyone tell how those are actually work in virtual machine... Is there any link for read?

Answer 1

Assuming you are only interested in how CPython does it' magic, look at Python/ceval.c , more specifically the _PyEval_EvalFrameDefault function. All the opcodes are right there.