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
instrsize(unsigned int oparg)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
write_op_arg(_Py_CODEUNIT * codestr,unsigned char opcode,unsigned int oparg,int ilen)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