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Elite on the BBC Micro

Version analysis of TWFR

This code appears in the following versions (click to see it in the source code):

Code variations between these versions are shown below.

Name: TWFR Type: Variable Category: Drawing lines Summary: Ready-made character rows for the right end of a horizontal line in mode 4

Code variation 1 of 1A variation in the comments only

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Cassette, Flight, Docked

6502SP

Ready-made bytes for plotting horizontal line end caps in mode 4 (the top part of the split screen). This table provides a byte with pixels at the right end, which is used for the left end of the line. See the HLOIN routine for details.
This table is not used by the 6502 Second Processor version of Elite. Instead, the TWFR table in the I/O processor code is used, which contains ready-made bytes for plotting horizontal line end caps in mode 1 (the top part of the split screen).
.TWFR EQUB %11111111 EQUB %01111111 EQUB %00111111 EQUB %00011111 EQUB %00001111 EQUB %00000111 EQUB %00000011 EQUB %00000001
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