PM0044 |
STM8 addressing modes |
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6.7Long Pointer Indirect Long addressing mode
The pointer address is a word, the pointer size is a word, thus allowing 64 KB addressing space, and requires 2 bytes after the op-code.
Example: |
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1040 |
42E5 |
ptr |
dc.w |
var |
1409 |
72C61040 |
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LD |
A,[longptr.w] |
42E5 |
11 |
var |
dc.b |
$11 |
Action:
A = [longptr.w] = ((longptr.w)) = (($1040.w)) = ($42E5) = $11
Figure 17. Long Pointer Indirect Long addressing mode example
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Before Completion |
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1040 |
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A |
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ptr .word var |
42 |
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E5 |
1041 |
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Previous Value |
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PC |
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LD A, [longptr.w] |
72 |
1409 |
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1409 |
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140A |
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C6 |
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140B |
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10 |
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40 |
140C |
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140D |
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EA |
42E5 |
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Steps to determine Effective Address
PC = 1409
PC = PC + 2 = 140B EA =((PC):(PC+1)):
((PC):(PC+1)+1) = 42E5
var.byte 0x011 |
11 |
42E5 |
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After Completion
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Instruction complete |
ptr .word var |
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1040 |
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42 |
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1041 |
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A = (EA) = 0x11 |
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E5 |
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New PC = PC + 2 = 140D |
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LD A, [longptr.w] |
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1409 |
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72 |
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140A |
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C6 |
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140B |
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10 |
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140C |
New PC |
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40 |
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140D |
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040D |
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A |
VR02059G |
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var .byte 0x11 |
11 |
42E5 |
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0x11 |
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Doc ID 13590 Rev 3 |
47/162 |