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Fix unaligned access in the VM code.

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* libguile/vm.c (struct t_32bit_aligned): New.
  (really_make_boot_program)[bytes]: Use it.  This fixes possibly
  unaligned accesses, which cause a "bus error" on some platforms (e.g.,
  sparc-*).
This commit is contained in:
Ludovic Courtès 2009-07-15 23:51:42 +02:00
parent b67cb2864e
commit 5bd047cefa
1 changed files with 27 additions and 7 deletions
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34
libguile/vm.c
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@ -227,21 +227,41 @@ static SCM make_u8vector (const scm_t_uint8 *bytes, size_t len)
return scm_take_u8vector (new_bytes, len);
}
/* Dummy structure to guarantee 32-bit alignment. */
struct t_32bit_aligned
{
scm_t_int32 dummy;
scm_t_uint8 bytes[18];
};
static SCM
really_make_boot_program (long nargs)
{
scm_byte_t bytes[] = {0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
scm_op_mv_call, 0, 0, 1, scm_op_make_int8_1, scm_op_halt};
SCM u8vec;
struct t_32bit_aligned bytes =
{
.dummy = 0,
.bytes = { 0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
scm_op_mv_call, 0, 0, 1,
scm_op_make_int8_1, scm_op_halt }
};
SCM ret;
((scm_t_uint32*)bytes)[1] = 6; /* set len in current endianness, no meta */
/* Set length in current endianness, no meta. */
((scm_t_uint32 *) bytes.bytes)[1] = 6;
if (SCM_UNLIKELY (nargs > 255 || nargs < 0))
abort ();
bytes[13] = (scm_byte_t)nargs;
ret = scm_make_program (scm_bytecode_to_objcode (make_u8vector (bytes, sizeof(bytes))),
bytes.bytes[13] = (scm_byte_t) nargs;
u8vec = make_u8vector (bytes.bytes, sizeof (bytes.bytes));
ret = scm_make_program (scm_bytecode_to_objcode (u8vec),
SCM_BOOL_F, SCM_EOL);
SCM_SET_SMOB_FLAGS (ret, SCM_F_PROGRAM_IS_BOOT);
return ret;
}
#define NUM_BOOT_PROGS 8