STM8 addressing modes |
PM0044 |
|
|
6.4.3SP Indexed addressing mode
The offset is a byte, thus require only one byte after the op-code, but only allow 00..(FF + stack top) addressing space.
Example: |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
0086 |
4B11 |
PUSH #$11 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
0087 |
4B22 |
PUSH #$22 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
0088 |
4B33 |
PUSH #$33 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
0089 |
7B03 |
LD A,($03,SP) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
Action: |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
A = ($03, SP) = ($03, $1FFC) = ($1FFF) = $11 |
|||||||||||||||||||
Figure 13. SP Indexed - 8-bit offset - addressing mode example |
||||||||||||||||||||
|
|
|
|
|
|
Before completion |
|
|
|
|
|
|||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PC |
|
|
|
|
Steps to determine |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
LD A, ($03,SP) |
7B |
0089 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
0089 |
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
effective address |
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||
|
|
03 |
008A |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
|
|
|
008B |
|
|
|
|
|
|
|
|
A |
|
|
|
|
PC = 0089 |
|||
|
|
|
|
|
|
|
|
|
Previous Value |
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PC = PC + 1 = 008A |
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
|
1FFC |
|
|
|
|
|
|
|
|
SP |
|
|
|
|
EA = (PC) + SP=03+1FFC= 1FFF |
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
1FFC |
|
|
|
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||
|
|
33 |
1FFD |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||
|
|
|
1FFE |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
22 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
11 |
1FFF |
|
|
|
|
1FFC |
|
|
03 |
|
|
|
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Adder |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
EA |
|
|
1FFF |
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
After completion |
|
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
LD A, ($03,SP) |
|
0089 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
7B |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Instruction Complete |
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
03 |
008A |
|
|
|
|
|
|
|
|
New PC |
|
|
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
008B |
|
|
|
|
|
|
|
|
008B |
|
|
|
|
A = (EA) = 11 |
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||
|
|
|
1FFC |
|
|
|
|
|
|
|
|
SP |
|
|
|
|
New PC = PC+1 = 008B |
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
|
|
|
|
1FFC |
|
|
|
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||
|
|
|
1FFD |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
33 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||
|
|
|
1FFE |
|
|
|
|
|
|
|
|
A |
|
|
|
|
|
|||
|
|
22 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||
|
|
11 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1FFF |
|
|
|
|
|
|
|
|
|
11 |
|
|
|
|
VR02059D |
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
42/162 |
Doc ID 13590 Rev 3 |