-#ifdef BITFIELD_CONS_EXPRESSIONS
-
-/* i960 assemblers, (eg, asm960), allow bitfields after ".byte" as
- w:x,y:z, where w and y are bitwidths and x and y are values. They
- then pack them all together. We do a little better in that we allow
- them in words, longs, etc. and we'll pack them in target byte order
- for you.
-
- The rules are: pack least significant bit first, if a field doesn't
- entirely fit, put it in the next unit. Overflowing the bitfield is
- explicitly *not* even a warning. The bitwidth should be considered
- a "mask".
-
- To use this function the tc-XXX.h file should define
- BITFIELD_CONS_EXPRESSIONS. */
-
-static void
-parse_bitfield_cons (expressionS *exp, unsigned int nbytes)
-{
- unsigned int bits_available = BITS_PER_CHAR * nbytes;
- char *hold = input_line_pointer;
-
- (void) expression (exp);
-
- if (*input_line_pointer == ':')
- {
- /* Bitfields. */
- long value = 0;
-
- for (;;)
- {
- unsigned long width;
-
- if (*input_line_pointer != ':')
- {
- input_line_pointer = hold;
- break;
- } /* Next piece is not a bitfield. */
-
- /* In the general case, we can't allow
- full expressions with symbol
- differences and such. The relocation
- entries for symbols not defined in this
- assembly would require arbitrary field
- widths, positions, and masks which most
- of our current object formats don't
- support.
-
- In the specific case where a symbol
- *is* defined in this assembly, we
- *could* build fixups and track it, but
- this could lead to confusion for the
- backends. I'm lazy. I'll take any
- SEG_ABSOLUTE. I think that means that
- you can use a previous .set or
- .equ type symbol. xoxorich. */
-
- if (exp->X_op == O_absent)
- {
- as_warn (_("using a bit field width of zero"));
- exp->X_add_number = 0;
- exp->X_op = O_constant;
- } /* Implied zero width bitfield. */
-
- if (exp->X_op != O_constant)
- {
- *input_line_pointer = '\0';
- as_bad (_("field width \"%s\" too complex for a bitfield"), hold);
- *input_line_pointer = ':';
- demand_empty_rest_of_line ();
- return;
- } /* Too complex. */
-
- if ((width = exp->X_add_number) > (BITS_PER_CHAR * nbytes))
- {
- as_warn (_("field width %lu too big to fit in %d bytes: truncated to %d bits"),
- width, nbytes, (BITS_PER_CHAR * nbytes));
- width = BITS_PER_CHAR * nbytes;
- } /* Too big. */
-
- if (width > bits_available)
- {
- /* FIXME-SOMEDAY: backing up and reparsing is wasteful. */
- input_line_pointer = hold;
- exp->X_add_number = value;
- break;
- } /* Won't fit. */
-
- /* Skip ':'. */
- hold = ++input_line_pointer;
-
- (void) expression (exp);
- if (exp->X_op != O_constant)
- {
- char cache = *input_line_pointer;
-
- *input_line_pointer = '\0';
- as_bad (_("field value \"%s\" too complex for a bitfield"), hold);
- *input_line_pointer = cache;
- demand_empty_rest_of_line ();
- return;
- } /* Too complex. */
-
- value |= ((~(-(1 << width)) & exp->X_add_number)
- << ((BITS_PER_CHAR * nbytes) - bits_available));
-
- if ((bits_available -= width) == 0
- || is_it_end_of_statement ()
- || *input_line_pointer != ',')
- {
- break;
- } /* All the bitfields we're gonna get. */
-
- hold = ++input_line_pointer;
- (void) expression (exp);
- }
-
- exp->X_add_number = value;
- exp->X_op = O_constant;
- exp->X_unsigned = 1;
- exp->X_extrabit = 0;
- }
-}
-
-#endif /* BITFIELD_CONS_EXPRESSIONS */
-\f