Test And Set operand

NAME
	TAS -- Test and set operand

SYNOPSIS
	TAS	<ea>

	Size = (Byte)

FUNCTION
	Test of a byte addressed by <ea>, bits N and Z of SR are set
	according to result of test.
	Bit 7 of byte is set to 1. This instruction uses read-modify-write
	cycle, which is not dividable and allows synchronisation of several
	processors. But this instruction is NOT ALLOWED ON AMIGA!
	This instruction can easily be substituted by BSET.

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

REGISTER
	<ea> is 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)+     |011 |N° reg. An| |   (d8,PC,Xi)  | -  |   -    |
	|-------------------------------| |-----------------------------|
	|    -(An)      |100 |N° reg. 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 byte is set. Cleared otherwise.
	Z - Set if byte is zero. Cleared otherwise.
	V - Always cleared.
	C - Always cleared.

SEE ALSO