
12
Chapter 1 Overview
1.7 Data Types
1.7.3 Bits
● Register bits
Figure 1.7.3 shows register bit specification.
Register bits can be specified by register direct (bit, Rn or bit, An). Use bit, Rn to specify a bit in data
register (Rn); use bit, An to specify a bit in address register (An).
Bits in each register are assigned bit numbers 0-15, from LSB to MSB. For bit in bit, Rn and bit, An, you
can specify a bit number in the range of 0 to 15.
Figure 1.7.3 Register bit specification
● Memory bits
Figure 1.7.4 shows addressing modes used for memory bit specification. Table 1.7.1 lists the address
range in which you can specify bits in each addressing mode. Be sure to observe the address range in
Table 1.7.1 when specifying memory bits.
b15 b0
bit,Rn
(bit: 0 to 15, n: 0 to 3)
Rn
b15 b0
bit,An
(bit: 0 to 15, n: 0 to 1)
An
bit,base:8
bit,base:16
bit,base:8[SB]
bit,base:11[SB]
bit,base:16[SB]
bit,base:8[FB]
[An]
base:8[An]
base:16[An]
Addressing modes
Absolute addressing
SB-based relative
addressing
FB-based relative
addressing
Address register-based indirect
addressing
Address register-based relative
addressing
bit,base:16
Figure 1.7.4 Addressing modes used for memory bit specification
Addressing Specification range
Remarks
Lower limit (address) Upper limit (address)
bit,base:16 0000016 01FFF16
bit,base:8[SB] [SB] [SB]+0001F16 The access range is 0000016 to 0FFFF16.
bit,base:11[SB] [SB] [SB]+000FF16 The access range is 0000016 to 0FFFF16.
bit,base:16[SB] [SB] [SB]+01FFF16 The access range is 0000016 to 0FFFF16.
bit,base:8[FB] [FB]Å|0001016 [FB]+0000F16 The access range is 0000016 to 0FFFF16.
[An] 0000016 01FFF16
base:8[An] base:8 base:8+01FFF16 The access range is 0000016 to 020FE16.
base:16[An] base:16 base:16+01FFF16 The access range is 0000016 to 0FFFF16.
Table 1.7.1 Bit-Specifying Address Range
Comentarios a estos manuales