Differences

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--- three_or_more_pass_assembly [2021/09/19 15:53] – created richardrussell
+++ three_or_more_pass_assembly [2024/01/05 00:21] (current) – external edit 127.0.0.1
@@ Line 36: / Line 36: @@
 </code>
-But wait, this is wrong!  The address of test% is **&09A31DB9** but the value pushed in the previous instruction is **&09A31DB6**.  BBC BASIC is broken!  I want my money back!
+But wait, this is wrong!  The address test% is **&09A31DB9** but the value pushed in the previous instruction is **&09A31DB6**.  BBC BASIC is broken!  I want my money back!
 No, it's not broken.  On the first pass the value of test% is **zero**, because it's declared as LOCAL, so the assembler encodes the 'push 0' as 6A 00.  But on the second pass the value of test% is no longer in the range -128 to +127 and therefore the assembler uses the long encoding: 68 B6 1D A3 09.  The resulting phase error causes the code emitted by the assembler to be invalid.