KBP

Name	Keyboard Process
Function	If the accumulator contains OOOOB, it remains unchanged. If one bit of the accumulator is set, the accumulator is set to a number from 1 to 4 indicating which bit was set.
Syntax	KBP
Assembled
Binary	11111100
Decimal	252
Hexadecimal	0xFC
Symbolic
Execution	1 word, 8-bit code and an execution time of 10.3 \({\mu}\) sec
Side-effects	Not Applicable
Implemented	kbp

Detailed Description

A code conversion is performed on the accumulator content, from 1 out of n to binary code. If the accumulator content has more than one bit on, the accumulator will be set to 15 (to indicate error). The carry/link is unaffected.

The conversion table is shown below:

Accumulator before KBP	Accumulator after KBP
0000	0000
0001	0001
0010	0010
0100	0011
1000	0100
0011	1111
0101	1111
0110	1111
0111	1111
1001	1111
1010	1111
1011	1111
1100	1111
1101	1111
1110	1111
1111	1111

The opcode for this instruction does not contain any additional data: