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Elite on the BBC Micro and NES

Universe: SOLAR

[BBC Micro cassette version]

Name: SOLAR [Show more] Type: Subroutine Category: Universe Summary: Set up various aspects of arriving in a new system
Context: See this subroutine in context in the source code Variations: See code variations for this subroutine in the different versions References: This subroutine is called as follows: * TT18 calls SOLAR

Halve our legal status, update the missile indicators, and set up data blocks and slots for the planet and sun.
.SOLAR LSR FIST \ Halve our legal status in FIST, making us less bad, \ and moving bit 0 into the C flag (so every time we \ arrive in a new system, our legal status improves a \ bit) JSR ZINF \ Call ZINF to reset the INWK ship workspace, which \ doesn't affect the C flag LDA QQ15+1 \ Fetch s0_hi AND #%00000111 \ Extract bits 0-2 (which also happen to determine the \ economy), which will be between 0 and 7 ADC #6 \ Add 6 + C, and divide by 2, to get a result between 3 LSR A \ and 7, at the same time shifting bit 0 of the result \ of the addition into the C flag STA INWK+8 \ Store the result in z_sign in byte #6 ROR A \ Halve A, rotating in the C flag, which was previously STA INWK+2 \ bit 0 of s0_hi + 6 + C, so when this is stored in both STA INWK+5 \ x_sign and y_sign, it moves the planet to the upper \ right or lower left JSR SOS1 \ Call SOS1 to set up the planet's data block and add it \ to FRIN, where it will get put in the first slot as \ it's the first one to be added to our local bubble of \ this new system's universe LDA QQ15+3 \ Fetch s1_hi, extract bits 0-2, set bits 0 and 7 and AND #%00000111 \ store in z_sign, so the sun is behind us at a distance ORA #%10000001 \ of 1 to 7 STA INWK+8 LDA QQ15+5 \ Fetch s2_hi, extract bits 0-1 and store in x_sign and AND #%00000011 \ y_sign, so the sun is either dead centre in our rear STA INWK+2 \ laser crosshairs, or off to the top left by a distance STA INWK+1 \ of 1 or 2 when we look out the back LDA #0 \ Set the pitch and roll counters to 0 (no rotation) STA INWK+29 STA INWK+30 LDA #129 \ Set A = 129, the ship type for the sun JSR NWSHP \ Call NWSHP to set up the sun's data block and add it \ to FRIN, where it will get put in the second slot as \ it's the second one to be added to our local bubble \ of this new system's universe