Some memory addressing schemes
Memory addressing 8088
1 Meg in 64K (16 bit) segments.
Two 16 bit address registers generate a 20 bit (1Meg) address range.
Pointer - bits 0-15 SI, DI, BP, SP
Segment - bits 4-20 CS, DS, SS, ES
Memory addressing 80386
Supports segmenting
Supports linear addressing.
Provides for 32 bit address register - 4GB.
Memory addressing 6502
16 bit linear addressing 64k bytes
Memory addressing 6510
4 banks of 64K bytes.
Memory addresses 0 and 1 connect to decoders rather than to storage.
Lower 4 bits of byte specifies 1 of 16 banks.
@0 - indicates the bank addressed by the program counter
@1 - indicates the bank addressed by instruction reads and writes.
Marie Virtual machine
16 bit instruction/operand 4 bits opcode, 12 bit operand
12 bit address range - single 4 K memory