Gotchas: Difference between revisions
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<lang 68000devpac>LEA $A04000,A0 ;effectively MOVEA.L #$A04000,A0 |
<lang 68000devpac>LEA $A04000,A0 ;effectively MOVEA.L #$A04000,A0 |
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LEA (4,A0),A0 ;effectively ADDA.L #4,A0</lang> |
LEA (4,A0),A0 ;effectively ADDA.L #4,A0</lang> |
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===Automatic Sign-Extension=== |
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When moving values into address registers ''at word length'', the value is sign-extended first. |
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<lang 68000devpac>MOVEA.W #$8000,A0 ;MOVEA.L #$FF8000,A0 |
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MOVEA.W #$7FFF,A0 ;MOVEA.L #$007FFF,A0</lang> |
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There is no sign-extension when moving values smaller than the data width into data registers, however. |
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<lang 68000devpac>MOVE.W #$FF,D0 ;MOVE.W #$00FF,D0 |
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MOVE.L #$8000,D2 ;MOVE.L #$00008000,D2</lang> |
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=={{header|MIPS Assembly}}== |
=={{header|MIPS Assembly}}== |