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cpython/Python/wordcode_helpers.h
Barry Warsaw b2e5794870 bpo-31338 (#3374)
* Add Py_UNREACHABLE() as an alias to abort().
* Use Py_UNREACHABLE() instead of assert(0)
* Convert more unreachable code to use Py_UNREACHABLE()
* Document Py_UNREACHABLE() and a few other macros.
2017-09-14 18:13:16 -07:00

45 lines
1.2 KiB
C

/* This file contains code shared by the compiler and the peephole
optimizer.
*/
#ifdef WORDS_BIGENDIAN
# define PACKOPARG(opcode, oparg) ((_Py_CODEUNIT)(((opcode) << 8) | (oparg)))
#else
# define PACKOPARG(opcode, oparg) ((_Py_CODEUNIT)(((oparg) << 8) | (opcode)))
#endif
/* Minimum number of code units necessary to encode instruction with
EXTENDED_ARGs */
static int
instrsize(unsigned int oparg)
{
return oparg <= 0xff ? 1 :
oparg <= 0xffff ? 2 :
oparg <= 0xffffff ? 3 :
4;
}
/* Spits out op/oparg pair using ilen bytes. codestr should be pointed at the
desired location of the first EXTENDED_ARG */
static void
write_op_arg(_Py_CODEUNIT *codestr, unsigned char opcode,
unsigned int oparg, int ilen)
{
switch (ilen) {
case 4:
*codestr++ = PACKOPARG(EXTENDED_ARG, (oparg >> 24) & 0xff);
/* fall through */
case 3:
*codestr++ = PACKOPARG(EXTENDED_ARG, (oparg >> 16) & 0xff);
/* fall through */
case 2:
*codestr++ = PACKOPARG(EXTENDED_ARG, (oparg >> 8) & 0xff);
/* fall through */
case 1:
*codestr++ = PACKOPARG(opcode, oparg & 0xff);
break;
default:
Py_UNREACHABLE();
}
}