GMS36 Datasheet, PDF (58/109 Pages) Hynix Semiconductor – 4-BIT SINGLE CHIP MICROCOMPUTERS

Chapter 5. INSTRUCTION
(26) DY
Naming :
Status :
Format :
Function :
<Purpose>
<Comment>
(27) EORM
Naming :
Status :
Format :
Function :
<Comment>
Decrement Y-Register and Status 1 on Not Borrow
é^{Carry to status}
Y à Y -1
ST à 1 (when Y ö 1)
ST à 0 (when Y = 0)
Data of the Y-register is decremented by one.
Data of the Y-register is decremented by one by addition of
minus 1 (Fh).
Carry data as results is transferred to the status. When the
results is equal to 15, the status is set to indicate that no
borrow has not occurred.
Exclusive or Memory and Accumulator
é^Set
A à M(X,Y) + A
Data of the accumulator is, through a Exclusive OR,
subtracted from the memory word addressed by X and Y-
register. Results are stored into the accumulator.
(28) NEGA
Naming :
Status :
Format :
Function :
<Purpose>
<Comment>
Negate Accumulator and Status 1 on Zero
é^{Carry to status}
A à A+1
ST à 1(when A = 0)
ST à 0 (when A != 0)
The 2`s complement of a word in the accumulator is obtained.
The 2`s complement in the accumulator is calculated by adding
one to the 1`s complement in the accumulator. Results are
stored into the accumulator. Carry data is transferred to the
status. When data of the accumulator is zero, a carry is
caused to set the status to Ì1Ì.
5-13