This instruction searches for the most significant bit
position that contains a 1. The bit position (the original bit offset plus the
offset of the first 1 bit) of that bit is placed in Dn. If no bit of the bit
field is 1, the value placed in Dn is the field offset plus field width. The
condition codes are set according to the value in the field.
ADDRESS METHODS: Dn, (An), x(An), x(An,xr.s), x.w, x.l, x(PC), x(PC,xr.s)
DATA LENGTH: Unsized
| FLAGS: | X - Not affected |
| N - Set if the most significant bit of the field is set. Cleared otherwise. | |
| Z - Set if all bits of the field are zero. Cleared otherwise. | |
| V - Always cleared. | |
| C - Always cleared. |
| SYNTAX: | BFFFO <ea>{offset:width},Dn |
The field selection is specified by a field offset and field width. The field offset denotes the starting bit of the field.. The field width determines the number of bits to be included in the field. The offset and width fields may be specified with an immediate operand ('#' is optional) or a data register. If the offset is an immediate operand the value must be in the range 0-31. If the offset is a data register the value is in the range -231 to 231-1. If the width is an immediate operand the value is in the range 1-31 or 0 to specify a width of 32. If the width is a data register the value is taken modulo 32, with values 1-31 or 0 to specify a width of 32. Bit 0 is the most significant bit.
BFFFO $1000{2,10},D1 finds the first 1 bit in the bits from $1000 bit 2 through $1000 bit 12 and put in D1