S3F9498 Datasheet, PDF (33/239 Pages) Samsung semiconductor – 8-BIT CMOS MICROCONTROLLER

ADDRESS SPACES
S3C9498/F9498
COMMON WORKING REGISTER AREA (C0H–CFH)
The SAM88RCRI register architecture provides an efficient method of working register addressing that takes full
advantage of shorter instruction formats to reduce execution time.
This 16-byte address range is called common area. That is, locations in this area can be used as working registers
by operations that address any location on any page in the register file.
Registers are addressed either as a single 8-bit register or as a paired 16-bit register. In 16-bit register pairs, the
address of the first 8-bit register is always an even number and the address of the next register is an odd number.
The most significant byte of the 16-bit data is always stored in the even-numbered register; the least significant
byte is always stored in the next (+ 1) odd-numbered register.
MSB
Rn
LSB
Rn+1
n = Even address
Figure 2-4. 16-Bit Register Pairs
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