NEGR - Revision history

Mr z: Protected "NEGR" ([edit=autoconfirmed] (indefinite) [move=autoconfirmed] (indefinite))

2010-12-04T09:00:50Z

Protected "NEGR" ([edit=autoconfirmed] (indefinite) [move=autoconfirmed] (indefinite))

Mr z at 19:36, 12 January 2005

2005-01-12T19:36:47Z

Pingaso at 17:55, 12 January 2005

2005-01-12T17:55:31Z

New page

[[Category:CP1610]]
<table border>
<tr><td>Instruction Name</td><td>Negate Register</td></tr>
<tr><td>Mnemonic</td><td>NEGR</td></tr>
<tr><td>CP1610 Clock Cycles</td><td>6</td></tr>
<tr><td>Interruptible</td><td>Yes</td></tr>
<tr><td>Opcode Range</td><td>$0020-$0027</td></tr>
<tr><td>Input Flags</td><td>None</td></tr>
<tr><td>Output Flags</td><td>[[Sign Flag]], [[Zero Flag]], [[Overflow Flag]], [[Carry Flag]]</td></tr>
</table><br/>
The Negate Register (NEGR) instruction creates a twos complement of the value in the specified register, stores the result in the same register, and sets or clears the [[Sign Flag]], [[Zero Flag]], [[Overflow Flag]], and [[Carry Flag]] according to the results. Note that a twos complement of any 16-bit value is equivalent to the value xor'ed with $FFFF and then adding one (1) to the result ((value^$FFFF)+1).<br/>

0000:0000:0010:0rrr<br/>
where:
rrr indicates the target register
such that:
rrr == 000 indicates register R0
rrr == 001 indicates register R1
rrr == 010 indicates register R2
rrr == 011 indicates register R3
rrr == 100 indicates register R4
rrr == 101 indicates register R5
rrr == 110 indicates register R6
rrr == 111 indicates register R7

← Older revision	Revision as of 09:00, 4 December 2010
(No difference)

@@ Line 9: / Line 9: @@
 <tr><td>Output Flags</td><td>[[Sign Flag]], [[Zero Flag]], [[Overflow Flag]], [[Carry Flag]]</td></tr>
 </table><br/>
-The Negate Register (NEGR) instruction creates a twos complement of the value in the specified register, stores the result in the same register, and sets or clears the [[Sign Flag]], [[Zero Flag]], [[Overflow Flag]], and [[Carry Flag]] according to the results. Note that a twos complement of any 16-bit value is equivalent to the value xor'ed with $FFFF and then adding one (1) to the result ((value^$FFFF)+1).<br/>
+The Negate Register (NEGR) instruction creates a 2s complement of the value in the specified register, stores the result in the same register, and sets or clears the [[Sign Flag]], [[Zero Flag]], [[Overflow Flag]], and [[Carry Flag]] according to the results.  The machine computes the 2s complement by inverting the number (e.g. XOR it with $FFFF) and then adding one (1) to the result ((value^$FFFF)+1).  Negating 0, for instance, sets the [[Carry Flag]].<br/>
 :0000:0010:0rrr<br/>