CoMPare Address
NAME
CMPA -- Compare address
SYNOPSIS
CMPA <ea>,An
Size = (Word, Long)
FUNCTION
Subtracts the source operand from the destination address
register and sets the condition codes according to the result. The
address register is NOT changed. Word sized source operands are
sign extended to long for comparison.
FORMAT
-----------------------------------------------------------------
|15 |14 |13 |12 |11 |10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|---|---|---|---|-----------|-----------|-----------|-----------|
| 1 | 0 | 1 | 1 | REGISTER | OP-MODE | MODE | REGISTER |
----------------------------------------=========================
<ea>
OP-MODE
011 16 bits operation.
111 32 bits operation.
REGISTER
The address register specifies destination An.
<ea> specifies source operand, addressing modes allowed are:
--------------------------------- -------------------------------
|Addressing Mode|Mode| Register | |Addressing Mode|Mode|Register|
|-------------------------------| |-----------------------------|
| Dn |000 |N° reg. Dn| | Abs.W |111 | 000 |
|-------------------------------| |-----------------------------|
| An |001 |N° reg. An| | Abs.L |111 | 001 |
|-------------------------------| |-----------------------------|
| (An) |010 |N° reg. An| | (d16,PC) |111 | 010 |
|-------------------------------| |-----------------------------|
| (An)+ |011 |N° reg. An| | (d8,PC,Xi) |111 | 011 |
|-------------------------------| |-----------------------------|
| -(An) |100 |N° reg. An| | (bd,PC,Xi) |111 | 011 |
|-------------------------------| |-----------------------------|
| (d16,An) |101 |N° reg. An| |([bd,PC,Xi],od)|111 | 011 |
|-------------------------------| |-----------------------------|
| (d8,An,Xi) |110 |N° reg. An| |([bd,PC],Xi,od)|111 | 011 |
|-------------------------------| |-----------------------------|
| (bd,An,Xi) |110 |N° reg. An| | #data |111 | 100 |
|-------------------------------| -------------------------------
|([bd,An,Xi]od) |110 |N° reg. An|
|-------------------------------|
|([bd,An],Xi,od)|110 |N° reg. An|
---------------------------------
RESULT
X - Not affected
N - Set if the result is negative. Cleared otherwise.
Z - Set if the result is zero. Cleared otherwise.
V - Set if an overflow occours. Cleared otherwise.
C - Set if a borrow occours. Cleared otherwise.
SEE ALSO
CMP CMPI CMP2
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& witbrock@cs.cmu.edu