ST72T311 ST Microelectronics, ST72T311 Datasheet - Page 80

• Manufacturer Part Number: ST72T311
• Description: 8-BIT MCU WITH 8 TO 16K OTP/EPROM
• Manufacturer: ST Microelectronics

ST72E311 ST72T311
5 INSTRUCTION SET
5.1 ST7 ADDRESSING MODES
The ST7 Core features 17 different addressing
modes which can be classified in 7 main groups:
The ST7 Instruction set is designed to minimize
the number of bytes required per instruction: To do
Table 22. ST7 Addressing Mode Overview
Note 1. At the time the instruction is executed, the Program Counter (PC) points to the instruction follow-
ing JRxx.
80/100
Addressing Mode
Inherent
Immediate
Direct
Indexed
Indirect
Relative
Bit operation
Inherent
Immediate
Short
Long
No Offset
Short
Long
Short
Long
Short
Long
Relative
Relative
Bit
Bit
Bit
Bit
80
Mode
Direct
Direct
Direct
Direct
Direct
Indirect
Indirect
Indirect
Indirect
Direct
Indirect
Direct
Indirect
Direct
Indirect
Indexed
Indexed
Indexed
Indexed
Indexed
Relative
Relative
Example
nop
ld A,#$55
ld A,$55
ld A,($55,X)
ld A,([$55],X)
jrne loop
bset
byte,#5
nop
ld A,#$55
ld A,$10
ld A,$1000
ld A,(X)
ld A,($10,X)
ld A,($1000,X)
ld A,[$10]
ld A,[$10.w]
ld A,([$10],X)
ld A,([$10.w],X)
jrne loop
jrne [$10]
bset $10,#7
bset [$10],#7
btjt $10,#7,skip
btjt [$10],#7,skip 00..FF
Syntax
00..FF
0000..FFFF
00..FF
00..1FE
0000..FFFF
00..FF
0000..FFFF
00..1FE
0000..FFFF
PC-128/PC+127
PC-128/PC+127
00..FF
00..FF
00..FF
Destination/
so, most of the addressing modes may be subdi-
vided in two sub-modes called long and short:
– Long addressing mode is more powerful be-
– Short addressing mode is less powerful because
The ST7 Assembler optimizes the use of long and
short addressing modes.
Source
cause it can use the full 64 Kbyte address space,
however it uses more bytes and more CPU cy-
cles.
it can generally only access page zero (0000h -
00FFh range), but the instruction size is more
compact, and faster. All memory to memory in-
structions use short addressing modes only
(CLR, CPL, NEG, BSET, BRES, BTJT, BTJF,
INC, DEC, RLC, RRC, SLL, SRL, SRA, SWAP)
1)
1)
00..FF
00..FF
00..FF
00..FF
00..FF
00..FF
00..FF
Address
Pointer
(Hex.)
byte
word
byte
word
byte
byte
byte
Pointer
(Hex.)
Size
+ 0
+ 1
+ 1
+ 2
+ 0 (with X register)
+ 1 (with Y register)
+ 1
+ 2
+ 2
+ 2
+ 2
+ 2
+ 1
+ 2
+ 1
+ 2
+ 2
+ 3
(Bytes)
Length