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⌂ ∞ ▽ Elite on the 6502

Version analysis of HATB

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

Code variations between these versions are shown below.

       Name: HATB
       Type: Variable
   Category: Ship hangar
    Summary: Ship hangar group table



 This table contains groups of ships to show in the ship hangar. A group of
 ships is shown half the time (the other half shows a solo ship), and each of
 the four groups is equally likely.

 The bytes for each ship in the group contain the following information:

   Byte #0             Non-zero = Ship type to draw
                       0        = don't draw anything

   Byte #1             Bits 0-7 = Ship's x_hi
                       Bit 0    = Ship's z_hi (1 if clear, or 2 if set)

   Byte #2             Bits 0-7 = Ship's z_lo
                       Bit 0    = Ship's x_sign

 The ship's y-coordinate is calculated in the has1 routine from the size of
 its targetable area. Ships of type 0 are not shown.

Code variation 1 of 14A variation in the comments only

This variation is blank in the 6502 Second Processor and Master versions.

Docked
 Note that ship numbers are for the ship hangar blueprints at XX21 in the
 docked code, rather than the full set of ships in the flight code. They are:

   1 = Cargo canister
   2 = Shuttle
   3 = Transporter
   4 = Cobra Mk III
   5 = Python
   6 = Viper
   7 = Krait

 There is one more ship blueprint in the docked code, for the Constrictor, but
 this is only used for showing the rotating ship in the mission 1 briefing. The
 Constrictor does not appear in the ship hangar.


.HATB

                        \ Hangar group for X = 0
                        \

Code variation 2 of 14Related to the Master version

In the disc and 6502SP versions, the first ship hangar group (of four) consists of a Transporter on the right and a Shuttle on the left, while in the Master version the first group has a lone Cobra Mk III on the left.

See below for more variations related to this code.

Tap on a block to expand it, and tap it again to revert.

Docked, 6502SP
Master
                        \ Shuttle (left) and Transporter (right)

                        \ Cobra Mk III (left)

Code variation 3 of 14Related to the Master version

See variation 2 above for details.

Tap on a block to expand it, and tap it again to revert.

Docked
Master
6502SP
 EQUB 2                 \ Ship type in the hangar = 2 = Shuttle

 EQUB 11                \ Ship type = 11 = Cobra Mk III

 EQUB 9                 \ Ship type = 9 = Shuttle

Code variation 4 of 14Related to the Master version

See variation 2 above for details.

Tap on a block to expand it, and tap it again to revert.

Docked, 6502SP
Master
 EQUB %01010100         \ x_hi = %01010100 = 84, z_hi   = 1     -> x = -84

 EQUB %01000100         \ x_hi = %01000100 = 68, z_hi   = 1     -> x = -68

 EQUB %00111011         \ z_lo = %00111011 = 59, x_sign = 1        z = +315

Code variation 5 of 14Related to the Master version

See variation 2 above for details.

Tap on a block to expand it, and tap it again to revert.

Docked
Master
6502SP
 EQUB 3                 \ Ship type in the hangar = 3 = Transporter

 EQUB 0                 \ No second ship

 EQUB 10                \ Ship type = 10 = Transporter

 EQUB %10000010         \ x_hi = %10000010 = 130, z_hi   = 1    -> x = +130
 EQUB %10110000         \ z_lo = %10110000 = 176, x_sign = 0       z = +432

 EQUB 0                 \ No third ship
 EQUB 0
 EQUB 0

                        \ Hangar group for X = 9
                        \
                        \ Three cargo canisters (left, far right and forward,
                        \ right)

Code variation 6 of 14Specific to an individual platform

Tap on a block to expand it, and tap it again to revert.

Docked
6502SP, Master
 EQUB 1                 \ Ship type in the hangar = 1 = Cargo canister

 EQUB OIL               \ Ship type = OIL = Cargo canister

 EQUB %01010000         \ x_hi = %01010000 = 80, z_hi   = 1     -> x = -80
 EQUB %00010001         \ z_lo = %00010001 = 17, x_sign = 1        z = +273

Code variation 7 of 14Specific to an individual platform

Tap on a block to expand it, and tap it again to revert.

Docked
6502SP, Master
 EQUB 1                 \ Ship type in the hangar = 1 = Cargo canister

 EQUB OIL               \ Ship type = OIL = Cargo canister

 EQUB %11010001         \ x_hi = %11010001 = 209, z_hi = 2      -> x = +209
 EQUB %00101000         \ z_lo = %00101000 =  40, x_sign = 0       z = +552

Code variation 8 of 14Specific to an individual platform

Tap on a block to expand it, and tap it again to revert.

Docked
6502SP, Master
 EQUB 1                 \ Ship type in the hangar = 1 = Cargo canister

 EQUB OIL               \ Ship type = OIL = Cargo canister

 EQUB %01000000         \ x_hi = %01000000 = 64, z_hi   = 1     -> x = +64
 EQUB %00000110         \ z_lo = %00000110 = 6,  x_sign = 0        z = +262

                        \ Hangar group for X = 18
                        \

Code variation 9 of 14Related to the BBC Micro disc version

In the disc version, the third ship hangar group (of four) consists of a Transporter on the right and a Cobra Mk III on the left, while in the advanced versions the third group has a Viper on the right and a Krait on the left.

See below for more variations related to this code.

Tap on a block to expand it, and tap it again to revert.

Docked
6502SP, Master
                        \ Transporter (right) and Cobra Mk III (left)

                        \ Viper (right) and Krait (left)

Code variation 10 of 14Related to the BBC Micro disc version

See variation 9 above for details.

Tap on a block to expand it, and tap it again to revert.

Docked
6502SP, Master
 EQUB 3                 \ Ship type in the hangar = 3 = Transporter

 EQUB COPS              \ Ship type = COPS = Viper

 EQUB %01100000         \ x_hi = %01100000 =  96, z_hi   = 1    -> x = +96
 EQUB %10010000         \ z_lo = %10010000 = 144, x_sign = 0       z = +400

Code variation 11 of 14Related to the BBC Micro disc version

See variation 9 above for details.

Tap on a block to expand it, and tap it again to revert.

Docked
6502SP, Master
 EQUB 4                 \ Ship type in the hangar = 4 = Cobra Mk III

 EQUB KRA               \ Ship type = KRA = Krait

 EQUB %00010000         \ x_hi = %00010000 =  16, z_hi   = 1    -> x = -16
 EQUB %11010001         \ z_lo = %11010001 = 209, x_sign = 1       z = +465

 EQUB 0                 \ No third ship
 EQUB 0
 EQUB 0

                        \ Hangar group for X = 27
                        \

Code variation 12 of 14Related to the Master version

In the disc and 6502SP versions, the fourth ship hangar group (of four) consists of a Viper on the right and a Krait on the left, while in the Master version the fourth group has an Adder on the right and a Viper on the left.

See below for more variations related to this code.

Tap on a block to expand it, and tap it again to revert.

Docked, 6502SP
Master
                        \ Viper (right and forward) and Krait (left)

                        \ Adder (right and forward) and Viper (left)

Code variation 13 of 14Related to the Master version

See variation 12 above for details.

Tap on a block to expand it, and tap it again to revert.

Docked
Master
6502SP
 EQUB 6                 \ Ship type in the hangar = 6 = Viper

 EQUB 20                \ Ship type = 20 = Adder

 EQUB 16                \ Ship type = 16 = Viper

 EQUB %01010001         \ x_hi = %01010001 =  81, z_hi  = 2     -> x = +81
 EQUB %11111000         \ z_lo = %11111000 = 248, x_sign = 0       z = +760

Code variation 14 of 14Related to the Master version

See variation 12 above for details.

Tap on a block to expand it, and tap it again to revert.

Docked
Master
6502SP
 EQUB 7                 \ Ship type in the hangar = 7 = Krait

 EQUB 16                \ Ship type = 16 = Viper

 EQUB 19                \ Ship type = 19 = Krait

 EQUB %01100000         \ x_hi = %01100000 = 96,  z_hi   = 1    -> x = -96
 EQUB %01110101         \ z_lo = %01110101 = 117, x_sign = 1       z = +373

 EQUB 0                 \ No third ship
 EQUB 0
 EQUB 0