GMS36 Datasheet, PDF (57/109 Pages) Hynix Semiconductor – 4-BIT SINGLE CHIP MICROCOMPUTERS

Chapter 5. INSTRUCTION
(23) IA
Naming :
Status :
Format :
Function :
<Comment>
(24) IY
Naming :
Status :
Format :
Function :
<Comment>
Increment Accumulator
é^Set
A à A+1
Data of the accumulator is incremented by one. Results are
returned to the accumulator.
A carry is not allowed to have effect upon the status.
Increment Y-Register and Status 1 on Carry
é^{Carry to status}
Y à Y+1
ST à 1 (when Y = 15)
ST à 0 (when Y < 15)
Data of the Y-register is incremented by one and results are
returned to the Y-register.
Carry data as results is transferred to the status. When the
total is more than 15, the status is set.
(25) DA
Naming :
Status :
Format :
Function :
<Comment>
Decrement Accumulator and Status 1 on Borrow
é^{Carry to status}
A à A -1
ST à 1(when A ö1)
ST à 0 (when A = 0)
Data of the accumulator is decremented by one. As a result
(by addition of Fh), if a borrow is caused, the status is reset to
Ì0Ì by logic. If the data is more than one, no borrow occurs
and thus the status is set to Ì1Ì.
5-12