Skip to navigation

BBC Micro Elite

Equipment: EQSHP

Name: EQSHP [View in context] Type: Subroutine Category: Equipment Summary: Show the Equip Ship screen (red key f3)
Other entry points: err Beep, pause and go to the docking bay (i.e. show the Status Mode screen)
.bay JMP BAY \ Go to the docking bay (i.e. show the Status Mode \ screen) .EQSHP JSR DIALS \ Call DIALS to update the dashboard LDA #32 \ Clear the top part of the screen, draw a white border, JSR TT66 \ and set the current view type in QQ11 to 32 (Equip \ Ship screen) LDA #12 \ Move the text cursor to column 12 STA XC LDA #207 \ Print recursive token 47 ("EQUIP") followed by a space JSR spc LDA #185 \ Print recursive token 25 ("SHIP") and draw a JSR NLIN3 \ horizontal line at pixel row 19 to box in the title LDA #%10000000 \ Set bit 7 of QQ17 to switch to Sentence Case, with the STA QQ17 \ next letter in capitals INC YC \ Move the text cursor down one line LDA tek \ Fetch the tech level of the current system from tek CLC \ and add 3 (the tech level is stored as 0-14, so A is ADC #3 \ now set to between 3 and 17) CMP #12 \ If A >= 12 then set A = 12, so A is now set to between BCC P%+4 \ 3 and 12 LDA #12 STA Q \ Set QQ25 = A (so QQ25 is in the range 3-12 and STA QQ25 \ represents number of the most advanced item available INC Q \ in this system, which we can pass to gnum below when \ asking which item we want to buy) \ \ Set Q = A + 1 (so Q is in the range 4-13 and contains \ QQ25 + 1, i.e. the highest item number on sale + 1) LDA #70 \ Set A = 70 - QQ14, where QQ14 contains the current SEC \ level in light years * 10, so this leaves the amount SBC QQ14 \ of fuel we need to fill 'er up (in light years * 10) ASL A \ The price of fuel is always 2 Cr per light year, so we STA PRXS \ double A and store it in PRXS, as the first price in \ the price list (which is reserved for fuel), and \ because the table contains prices as price * 10, it's \ in the right format (so a full tank, or 7.0 light \ years, would be 14.0 Cr, or a PRXS value of 140) LDX #1 \ We are now going to work our way through the equipment \ price list at PRXS, printing out the equipment that is \ available at this station, so set a counter in X, \ starting at 1, to hold the number of the current item \ plus 1 (so the item number in X loops through 1-13) .EQL1 STX XX13 \ Store the current item number + 1 in XX13 JSR TT67 \ Print a newline LDX XX13 \ Print the current item number + 1 to 3 digits, left- CLC \ padding with spaces, and with no decimal point, so the JSR pr2 \ items are numbered from 1 JSR TT162 \ Print a space LDA XX13 \ Print recursive token 104 + XX13, which will be in the CLC \ range 105 ("FUEL") to 116 ("GALACTIC HYPERSPACE ") ADC #104 \ so this prints the current item's name JSR TT27 LDA XX13 \ Call prx-3 to set (Y X) to the price of the item with JSR prx-3 \ number XX13 - 1 (as XX13 contains the item number + 1) SEC \ Set the C flag so we will print a decimal point when \ we print the price LDA #25 \ Move the text cursor to column 25 STA XC LDA #6 \ Print the number in (Y X) to 6 digits, left-padding JSR TT11 \ with spaces and including a decimal point, which will \ be the correct price for this item as (Y X) contains \ the price * 10, so the trailing zero will go after the \ decimal point (i.e. 5250 will be printed as 525.0) LDX XX13 \ Increment the current item number in XX13 INX CPX Q \ If X < Q, loop back up to print the next item on the BCC EQL1 \ list of equipment available at this station JSR CLYNS \ Clear the bottom three text rows of the upper screen, \ and move the text cursor to column 1 on row 21, i.e. \ the start of the top row of the three bottom rows LDA #127 \ Print recursive token 127 ("ITEM") followed by a JSR prq \ question mark JSR gnum \ Call gnum to get a number from the keyboard, which \ will be the number of the item we want to purchase, \ returning the number entered in A and R, and setting \ the C flag if the number is bigger than the highest \ item number in QQ25 BEQ bay \ If no number was entered, jump up to bay to go to the \ docking bay (i.e. show the Status Mode screen) BCS bay \ If the number entered was too big, jump up to bay to \ go to the docking bay (i.e. show the Status Mode \ screen) SBC #0 \ Set A to the number entered - 1 (because the C flag is \ clear), which will be the actual item number we want \ to buy LDX #2 \ Move the text cursor to column 2 on the next line STX XC INC YC PHA \ While preserving the value in A, call eq to subtract JSR eq \ the price of the item we want to buy (which is in A) PLA \ from our cash pot, but only if we have enough cash in \ the pot. If we don't have enough cash, exit to the \ docking bay (i.e. show the Status Mode screen) BNE et0 \ If A is not 0 (i.e. the item we've just bought is not \ fuel), skip to et0 STA MCNT \ We just bought fuel, so we zero the main loop counter LDX #70 \ And set the current fuel level * 10 in QQ14 to 70, or STX QQ14 \ 7.0 light years (a full tank) .et0 CMP #1 \ If A is not 1 (i.e. the item we've just bought is not BNE et1 \ a missile), skip to et1 LDX NOMSL \ Fetch the current number of missiles from NOMSL into X INX \ Increment X to the new number of missiles LDY #117 \ Set Y to recursive token 117 ("ALL") CPX #5 \ If buying this missile would give us 5 missiles, this BCS pres \ is more than the maximum of 4 missiles that we can \ fit, so jump to pres to show the error "All Present", \ beep and exit to the docking bay (i.e. show the Status \ Mode screen) STX NOMSL \ Otherwise update the number of missiles in NOMSL JSR msblob \ And call msblob to update the dashboard's missile \ indicators with our new purchase .et1 LDY #107 \ Set Y to recursive token 107 ("LARGE CARGO{switch to \ sentence case} BAY") CMP #2 \ If A is not 2 (i.e. the item we've just bought is not BNE et2 \ a large cargo bay), skip to et2 LDX #37 \ If our current cargo capacity in CRGO is 37, then we CPX CRGO \ already have a large cargo bay fitted, so jump to pres BEQ pres \ to show the error "Large Cargo Bay Present", beep and \ exit to the docking bay (i.e. show the Status Mode \ screen) STX CRGO \ Otherwise we just scored ourselves a large cargo bay, \ so update our current cargo capacity in CRGO to 37 .et2 CMP #3 \ If A is not 3 (i.e. the item we've just bought is not BNE et3 \ an E.C.M. system), skip to et3 INY \ Increment Y to recursive token 108 ("E.C.M.SYSTEM") LDX ECM \ If we already have an E.C.M. fitted (i.e. ECM is BNE pres \ non-zero), jump to pres to show the error "E.C.M. \ System Present", beep and exit to the docking bay \ (i.e. show the Status Mode screen) DEC ECM \ Otherwise we just took delivery of a brand new E.C.M. \ system, so set ECM to &FF (as ECM was 0 before the DEC \ instruction) .et3 CMP #4 \ If A is not 4 (i.e. the item we've just bought is not BNE et4 \ an extra pulse laser), skip to et4 JSR qv \ Print a menu listing the four views, with a "View ?" \ prompt, and ask for a view number, which is returned \ in X (which now contains 0-3) LDA #4 \ This instruction doesn't appear to do anything, as we \ either don't need it (if we already have this laser) \ or we set A to 4 below (if we buy it) LDY LASER,X \ If there is no laser mounted in the chosen view (i.e. BEQ ed4 \ LASER+X, which contains the laser power for view X, is \ zero), jump to ed4 to buy a pulse laser .ed7 LDY #187 \ Otherwise we already have a laser mounted in this BNE pres \ view, so jump to pres with Y set to token 27 \ (" LASER") to show the error "Laser Present", beep \ and exit to the docking bay (i.e. show the Status \ Mode screen) .ed4 LDA #POW \ We just bought a pulse laser for view X, so we need STA LASER,X \ to fit it by storing the laser power for a pulse laser \ (given in POW) in LASER+X LDA #4 \ Set A to 4 as we just overwrote the original value, \ and we still need it set correctly so we can continue \ through the conditional statements for all the other \ equipment .et4 CMP #5 \ If A is not 5 (i.e. the item we've just bought is not BNE et5 \ an extra beam laser), skip to et5 JSR qv \ Print a menu listing the four views, with a "View ?" \ prompt, and ask for a view number, which is returned \ in X (which now contains 0-3) STX T1 \ Store the view in T1 so we can retrieve it below LDA #5 \ Set A to 5 as the call to qv will have overwritten \ the original value, and we still need it set \ correctly so we can continue through the conditional \ statements for all the other equipment LDY LASER,X \ If there is no laser mounted in the chosen view (i.e. BEQ ed5 \ LASER+X, which contains the laser power for mount X, \ is zero), jump to ed5 to buy a beam laser \BPL P%+4 \ This instruction is commented out in the original \ source, though it would have no effect (it would \ simply skip the BMI if A is positive, which is what \ BMI does anyway) BMI ed7 \ If there is a beam laser already mounted in the chosen \ view (i.e. LASER+X has bit 7 set, which indicates a \ beam laser rather than a pulse laser), skip back to \ ed7 to print a "Laser Present" error, beep and exit \ to the docking bay (i.e. show the Status Mode screen) LDA #4 \ If we get here then we already have a pulse laser in JSR prx \ the selected view, so we call prx to set (Y X) to the \ price of equipment item number 4 (extra pulse laser) \ so we can give a refund of the pulse laser JSR MCASH \ Add (Y X) cash to the cash pot in CASH, so we refund \ the price of the pulse laser we are exchanging for a \ new beam laser .ed5 LDA #POW+128 \ We just bought a beam laser for view X, so we need LDX T1 \ to mount it by storing the laser power for a beam STA LASER,X \ laser (given in POW+128) in LASER+X, using the view \ number we stored in T1 earlier, as the call to prx \ will have overwritten the original value in X .et5 LDY #111 \ Set Y to recursive token 107 ("FUEL SCOOPS") CMP #6 \ If A is not 6 (i.e. the item we've just bought is not BNE et6 \ a fuel scoop), skip to et6 LDX BST \ If we already have fuel scoops fitted (i.e. BST is BEQ ed9 \ zero), jump to ed9, otherwise fall through into pres \ to show the error "Fuel Scoops Present", beep and \ exit to the docking bay (i.e. show the Status Mode \ screen) .pres \ If we get here we need to show an error to say that \ item number A is already present, where the item's \ name is recursive token Y STY K \ Store the item's name in K JSR prx \ Call prx to set (Y X) to the price of equipment item \ number A JSR MCASH \ Add (Y X) cash to the cash pot in CASH, as the station \ already took the money for this item in the JSR eq \ instruction above, but we can't fit the item, so need \ our money back LDA K \ Print the recursive token in K (the item's name) JSR spc \ followed by a space LDA #31 \ Print recursive token 145 ("PRESENT") JSR TT27 .err JSR dn2 \ Call dn2 to make a short, high beep and delay for 1 \ second JMP BAY \ Jump to BAY to go to the docking bay (i.e. show the \ Status Mode screen) .ed9 DEC BST \ We just bought a shiny new fuel scoop, so set BST to \ &FF (as BST was 0 before the jump to ed9 above) .et6 INY \ Increment Y to recursive token 112 ("E.C.M.SYSTEM") CMP #7 \ If A is not 7 (i.e. the item we've just bought is not BNE et7 \ an escape pod), skip to et7 LDX ESCP \ If we already have an escape pod fitted (i.e. ESCP is BNE pres \ non-zero), jump to pres to show the error "Escape Pod \ Present", beep and exit to the docking bay (i.e. show \ the Status Mode screen) DEC ESCP \ Otherwise we just bought an escape pod, so set ESCP \ to &FF (as ESCP was 0 before the DEC instruction) .et7 INY \ Increment Y to recursive token 113 ("ENERGY BOMB") CMP #8 \ If A is not 8 (i.e. the item we've just bought is not BNE et8 \ an energy bomb), skip to et8 LDX BOMB \ If we already have an energy bomb fitted (i.e. BOMB BNE pres \ is non-zero), jump to pres to show the error "Energy \ Bomb Present", beep and exit to the docking bay (i.e. \ show the Status Mode screen) LDX #&7F \ Otherwise we just bought an energy bomb, so set BOMB STX BOMB \ to &7F .et8 INY \ Increment Y to recursive token 114 ("ENERGY UNIT") CMP #9 \ If A is not 9 (i.e. the item we've just bought is not BNE etA \ an energy unit), skip to etA LDX ENGY \ If we already have an energy unit fitted (i.e. ENGY is BNE pres \ non-zero), jump to pres to show the error "Energy Unit \ Present", beep and exit to the docking bay (i.e. show \ the Status Mode screen) INC ENGY \ Otherwise we just picked up an energy unit, so set \ ENGY to 1 (as ENGY was 0 before the INC instruction) .etA INY \ Increment Y to recursive token 115 ("DOCKING \ COMPUTERS") CMP #10 \ If A is not 10 (i.e. the item we've just bought is not BNE etB \ a docking computer), skip to etB LDX DKCMP \ If we already have a docking computer fitted (i.e. BNE pres \ DKCMP is non-zero), jump to pres to show the error \ "Docking Computer Present", beep and exit to the \ docking bay (i.e. show the Status Mode screen) DEC DKCMP \ Otherwise we just got hold of a docking computer, so \ set DKCMP to &FF (as DKCMP was 0 before the DEC \ instruction) .etB INY \ Increment Y to recursive token 116 ("GALACTIC \ HYPERSPACE ") CMP #11 \ If A is not 11 (i.e. the item we've just bought is not BNE et9 \ a galactic hyperdrive), skip to et9 LDX GHYP \ If we already have a galactic hyperdrive fitted (i.e. BNE pres \ GHYP is non-zero), jump to pres to show the error \ "Galactic Hyperspace Present", beep and exit to the \ docking bay (i.e. show the Status Mode screen) DEC GHYP \ Otherwise we just splashed out on a galactic \ hyperdrive, so set GHYP to &FF (as GHYP was 0 before \ the DEC instruction) .et9 JSR dn \ We are done buying equipment, so print the amount of \ cash left in the cash pot, then make a short, high \ beep to confirm the purchase, and delay for 1 second JMP EQSHP \ Jump back up to EQSHP to show the Equip Ship screen \ again and see if we can't track down another bargain