Bit Field CLeaR

NAME
	BFCLR -- Bit field clear

SYNOPSIS
	BFCLR	<ea>{OFFSET:WIDTH}	(68020+)

	No size specs.

FUNCTION
	<ea> indicates destination operand which a part of bits have to be
	cleared. Offset enables to locate first bit of field; width specifies
	number of bits of this field. Field is tested, flags are set, and bits
	of field are cleared.
	Be careful, this instruction operates from MSB to LSB!!

FORMAT
	                                                  <ea>
	----------------------------------------=========================
	|15 |14 |13 |12 |11 |10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
	|---|---|---|---|---|---|---|---|---|---|-----------|-----------|
	| 1 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 |    MODE   | REGISTER  |
	|---|---|---|---|---|-------------------|-----------------------|
	| 0 | 0 | 0 | 0 |Do |       OFFSET      |Dw |      WIDTH        |
	-----------------------------------------------------------------

	If Do = 0->Field "OFFSET" contains an immediate value which represents
	effective offset, value from 0 to 31.
	If Do = 1->Field "OFFSET" indicates number of a data register (bits 9
	and 10 of field cleared) which contains effective offset. Signed value
	is represented on 32 bits., so it's extended from -2 EXP 31 to
	(+2 EXP 31) -1.

	If Dw = 0->field "WIDTH" contains an immediate value between 1 and 31
	which indicates a width from 1 to 31 bits. A value of 0 indicates a
	width of 32 bits.
	If Dw = 1->field "WIDTH" indicates number of a data register (bits 3
	and 4 of field cleared) which contains width of bit field. The value
	modulo 32 can go from 1 to 31, indicating a width from 1 to 31 bits.
	A value 0 indicates a width of 32 bits.

REGISTER
	<ea> is always destination, addressing modes are the followings:
	--------------------------------- -------------------------------
	|Addressing Mode|Mode| Register | |Addressing Mode|Mode|Register|
	|-------------------------------| |-----------------------------|
	|      Dn       |000 |N° reg. Dn| |    Abs.W      |111 |  000   |
	|-------------------------------| |-----------------------------|
	|      An       | -  |     -    | |    Abs.L      |111 |  001   |
	|-------------------------------| |-----------------------------|
	|     (An)      |010 |N° reg. An| |   (d16,PC)    | -  |   -    |
	|-------------------------------| |-----------------------------|
	|     (An)+     | -  |     -    | |   (d8,PC,Xi)  | -  |   -    |
	|-------------------------------| |-----------------------------|
	|    -(An)      | -  |     -    | |   (bd,PC,Xi)  | -  |   -    |
	|-------------------------------| |-----------------------------|
	|    (d16,An)   |101 |N° reg. An| |([bd,PC,Xi],od)| -  |   -    | 
	|-------------------------------| |-----------------------------|
	|   (d8,An,Xi)  |110 |N° reg. An| |([bd,PC],Xi,od)| -  |   -    |
	|-------------------------------| |-----------------------------|
	|   (bd,An,Xi)  |110 |N° reg. An| |    #data      | -  |   -    |
	|-------------------------------| -------------------------------
	|([bd,An,Xi]od) |110 |N° reg. An|
	|-------------------------------|
	|([bd,An],Xi,od)|110 |N° reg. An|
	---------------------------------

RESULT
	X - not affected
	N - Set if MSB of field is set. Cleared otherwise.
	Z - Set if all the bits of the field tested are zero.
	    Cleared otherwise.
	V - Always cleared.
	C - Always cleared.

SEE ALSO
	BFCHG	BFSET