NEC PD754244 Network Card User Manual


 
CHAPTER 3 FEATURES OF ARCHITECTURE AND MEMORY MAP
36 Users Manual U10676EJ3V0UM
Table 3-1. Addressing Modes
Addressing Mode Representation Specified Address
When MBE = 0
When mem = 00H to 7FH: MB = 0
When mem = 80H to FFH: MB = 15
When MBE = 1: MB = MBS
4-bit direct addressing mem Address specified by MB and mem.
When MBE = 0
When mem = 00H to 7FH: MB = 0
When mem = 80H to FFH: MB = 15
When MBE = 1: MB = MBS
8-bit direct addressing Address specified by MB and mem (mem is even address)
When MBE = 0
When mem = 00H to 7FH: MB = 0
When mem = 80H to FFH: MB = 15
When MBE = 1: MB = MBS
4-bit register indirect @HL Address specified by MB and HL.
addressing Where, MB = MBE MBS
@HL+ Address specified by MB and HL. However, MB = MBE
MBS.
@HL HL+ automatically increments L register after addressing.
HL automatically decrements L register after addressing.
@DE Address specified by DE in memory bank 0
@DL Address specified by DL in memory bank 0
8-bit register indirect @HL Address specified by MB and HL (contents of L register are even
addressing number)
Where, MB = MBE MBS
Bit manipulation fmem.bit Bit specified by bit at address specified by fmem
addressing fmem = FB0H to FBFH (interrupt-related hardware)
FF0H to FFFH (I/O port)
pmem.@L Bit specified by lower 2 bits of L register at address specified by
higher 10 bits of pmem and lower 2 bits of L register.
Where, pmem = FC0H to FFFH
@H+mem.bit Bit specified by bit at address specified by MB, H, and lower 4 bits
of mem.
Where, MB = MBE MBS
Stack addressing Address specified by SP in memory bank 0
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