gc80c520a CORERIVER Semiconductor, gc80c520a Datasheet - Page 110

• Manufacturer Part Number: gc80c520a
• Description: Midas1.0 Family Mask Rom/eprom/romless 8-bit Turbo Microcontrollers
• Manufacturer: CORERIVER Semiconductor

Instruction Set
DEC
DPTR
Function:
Decrement Data Pointer
16
Decrement the 16-bit data pointer by 1. A 16-bit decrement (modulo 2
) is
Description:
performed; an underflow of the low-order byte of the data pointer (DPL) from
0FFH to 00H will decrement the high-order byte (DPH). No flags are affected.
This is the only 16-bit register which can be decremented.
Example:
Registers DPH and DPL contain 12h and 01h, respectively. The instruction
sequence,
DEC DPTR
DEC DPTR
DEC DPTR
will change DPH and DPL to 11h and 0FEh.
1
Bytes:
Cycles:
1
1
0
1
0
0 1 0 1
Encoding:
Preliminary
Operation:
DEC
←
(DPTR)
(DPTR) - 1
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