STM8 addressing modes |
PM0044 |
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6.3.1Short Direct addressing mode
The address is a byte, thus require only one byte after the op-code, but only allow 00..FF addressing space.
Example: |
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004B |
20 |
coeff |
dc.b |
$20 |
052D |
B64B |
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LD |
A,coeff |
Action:
A = (coeff) = ($4B) = $20
Figure 8. Short Direct addressing mode example
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Before Completion |
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A |
Coeff .byte 20h |
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20 |
004B |
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Previous Value |
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PC |
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B6 |
052D |
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052D |
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LD A,Coeff |
4B |
052E |
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052F |
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Steps to Determine Effective Address
PC = 052D
PC = PC + 1 = 052E EA = (PC)
=(4B + 0000)
=004B
EA 004B
After Completion
Coeff .byte 20h |
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A |
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20 |
004B |
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20 |
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Instruction Complete |
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B6 |
052D |
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A = (EA) = 20 |
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LD A,Coeff |
4B |
052E |
New PC |
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New PC = PC +1 =052F |
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052F |
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052F |
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VR02059L |
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36/162 |
Doc ID 13590 Rev 3 |