1 | /* This file contains code shared by the compiler and the peephole |
2 | optimizer. |
3 | */ |
4 | |
5 | #ifdef WORDS_BIGENDIAN |
6 | # define PACKOPARG(opcode, oparg) ((_Py_CODEUNIT)(((opcode) << 8) | (oparg))) |
7 | #else |
8 | # define PACKOPARG(opcode, oparg) ((_Py_CODEUNIT)(((oparg) << 8) | (opcode))) |
9 | #endif |
10 | |
11 | /* Minimum number of code units necessary to encode instruction with |
12 | EXTENDED_ARGs */ |
13 | static int |
14 | instrsize(unsigned int oparg) |
15 | { |
16 | return oparg <= 0xff ? 1 : |
17 | oparg <= 0xffff ? 2 : |
18 | oparg <= 0xffffff ? 3 : |
19 | 4; |
20 | } |
21 | |
22 | /* Spits out op/oparg pair using ilen bytes. codestr should be pointed at the |
23 | desired location of the first EXTENDED_ARG */ |
24 | static void |
25 | write_op_arg(_Py_CODEUNIT *codestr, unsigned char opcode, |
26 | unsigned int oparg, int ilen) |
27 | { |
28 | switch (ilen) { |
29 | case 4: |
30 | *codestr++ = PACKOPARG(EXTENDED_ARG, (oparg >> 24) & 0xff); |
31 | /* fall through */ |
32 | case 3: |
33 | *codestr++ = PACKOPARG(EXTENDED_ARG, (oparg >> 16) & 0xff); |
34 | /* fall through */ |
35 | case 2: |
36 | *codestr++ = PACKOPARG(EXTENDED_ARG, (oparg >> 8) & 0xff); |
37 | /* fall through */ |
38 | case 1: |
39 | *codestr++ = PACKOPARG(opcode, oparg & 0xff); |
40 | break; |
41 | default: |
42 | Py_UNREACHABLE(); |
43 | } |
44 | } |
45 | |