Philips Semiconductors
8-bit microcontrollers
9.3 Addressing
The P83C528 has five modes for addressing:
• Register
• Direct
• Register-Indirect
• Immediate
• Base-Register plus Index-Register-Indirect.
The first three methods can be used for addressing
destination operands. Most instructions have a
'destination/source' field that specifies the data type,
addressing methods and operands involved. For
operations other than MOVs, the destination operand is
also a source operand.
Access to memory addresses is as follows:
• Register in one of the four 8-bit register banks through
Register, Direct or Register-Indirect addressing.
• 512 bytes of internal RAM through Direct or
Register-Indirect addressing. Bytes 0-127 of internal
RAM may be addressed directly/indirectly. Bytes
128-255 of internal RAM share their address location
with the SFRs and so may only be addressed indirectly
as data RAM. Bytes 0-255 of AUX-RAM can only be
addressed indirectly via MOVX.
• SFR through Direct addressing at address locations
128-255.
• External data memory through Register-Indirect
addressing.
• Program memory look-up tables through Base-Register
plus Index-Register-Indirect addressing.
Product specification
P83C524; P80C528; P83C528
1997 Dec 15
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