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BBC Micro Elite

Universe: TT25

Name: TT25 [View in context] Type: Subroutine Category: Universe Summary: Show the Data on System screen (red key f6)
Other entry points: TT72 Used by TT70 to re-enter the routine after displaying "MAINLY" for the economy type
.TT25 JSR TT66-2 \ Clear the top part of the screen, draw a white border, \ and set the current view type in QQ11 to 1 LDA #9 \ Set the text cursor XC to column 9 STA XC LDA #163 \ Print recursive token 3 as a title in capitals at JSR TT27 \ the top ("DATA ON {selected system name}") JSR NLIN \ Draw a horizontal line underneath the title JSR TTX69 \ Print a paragraph break and set Sentence Case INC YC \ Move the text cursor down one more line JSR TT146 \ If the distance to this system is non-zero, print \ "DISTANCE", then the distance, "LIGHT YEARS" and a \ paragraph break, otherwise just move the cursor down \ a line LDA #194 \ Print recursive token 34 ("ECONOMY") followed by JSR TT68 \ a colon LDA QQ3 \ The system economy is determined by the value in QQ3, \ so fetch it into A. First we work out the system's \ prosperity as follows: \ \ QQ3 = 0 or 5 = %000 or %101 = Rich \ QQ3 = 1 or 6 = %001 or %110 = Average \ QQ3 = 2 or 7 = %010 or %111 = Poor \ QQ3 = 3 or 4 = %011 or %100 = Mainly CLC \ If (QQ3 + 1) >> 1 = %10, i.e. if QQ3 = %011 or %100 ADC #1 \ (3 or 4), then call TT70, which prints "MAINLY " and LSR A \ jumps down to TT72 to print the type of economy CMP #%00000010 BEQ TT70 LDA QQ3 \ The LSR A above shifted bit 0 of QQ3 into the C flag, BCC TT71 \ so this jumps to TT71 if bit 0 of QQ3 is 0, in other \ words if QQ3 = %000, %001 or %010 (0, 1 or 2) SBC #5 \ Here QQ3 = %101, %110 or %111 (5, 6 or 7), so subtract CLC \ 5 to bring it down to 0, 1 or 2 (the C flag is already \ set so the SBC will be correct) .TT71 ADC #170 \ A is now 0, 1 or 2, so print recursive token 10 + A. JSR TT27 \ This means that: \ \ QQ3 = 0 or 5 prints token 10 ("RICH ") \ QQ3 = 1 or 6 prints token 11 ("AVERAGE ") \ QQ3 = 2 or 7 prints token 12 ("POOR ") .TT72 LDA QQ3 \ Now to work out the type of economy, which is LSR A \ determined by bit 2 of QQ3, as follows: LSR A \ \ QQ3 bit 2 = 0 = Industrial \ QQ3 bit 2 = 1 = Agricultural \ \ So we fetch QQ3 into A and set A = bit 2 of QQ3 using \ two right shifts (which will work as QQ3 is only a \ 3-bit number) CLC \ Print recursive token 8 + A, followed by a paragraph ADC #168 \ break and Sentence Case, so: JSR TT60 \ \ QQ3 bit 2 = 0 prints token 8 ("INDUSTRIAL") \ QQ3 bit 2 = 1 prints token 9 ("AGRICULTURAL") LDA #162 \ Print recursive token 2 ("GOVERNMENT") followed by JSR TT68 \ a colon LDA QQ4 \ The system economy is determined by the value in QQ4, \ so fetch it into A CLC \ Print recursive token 17 + A, followed by a paragraph ADC #177 \ break and Sentence Case, so: JSR TT60 \ \ QQ4 = 0 prints token 17 ("ANARCHY") \ QQ4 = 1 prints token 18 ("FEUDAL") \ QQ4 = 2 prints token 19 ("MULTI-GOVERNMENT") \ QQ4 = 3 prints token 20 ("DICTATORSHIP") \ QQ4 = 4 prints token 21 ("COMMUNIST") \ QQ4 = 5 prints token 22 ("CONFEDERACY") \ QQ4 = 6 prints token 23 ("DEMOCRACY") \ QQ4 = 7 prints token 24 ("CORPORATE STATE") LDA #196 \ Print recursive token 36 ("TECH.LEVEL") followed by a JSR TT68 \ colon LDX QQ5 \ Fetch the tech level from QQ5 and increment it, as it INX \ is stored in the range 0-14 but the displayed range \ should be 1-15 CLC \ Call pr2 to print the technology level as a 3-digit JSR pr2 \ number without a decimal point (by clearing the C \ flag) JSR TTX69 \ Print a paragraph break and set Sentence Case LDA #192 \ Print recursive token 32 ("POPULATION") followed by a JSR TT68 \ colon SEC \ Call pr2 to print the population as a 3-digit number LDX QQ6 \ with a decimal point (by setting the C flag), so the JSR pr2 \ number printed will be population / 10 LDA #198 \ Print recursive token 38 (" BILLION"), followed by a JSR TT60 \ paragraph break and Sentence Case LDA #'(' \ Print an opening bracket JSR TT27 LDA QQ15+4 \ Now to calculate the species, so first check bit 7 of BMI TT75 \ w2_lo, and if it is set, jump to TT75 as this is an \ alien species LDA #188 \ Bit 7 of w2_lo is clear, so print recursive token 28 JSR TT27 \ ("HUMAN COLONIAL") JMP TT76 \ Jump to TT76 to print "S)" and a paragraph break, so \ the whole species string is "(HUMAN COLONIALS)" .TT75 LDA QQ15+5 \ This is an alien species, and we start with the first LSR A \ adjective, so fetch bits 2-7 of w2_hi into A and push LSR A \ onto the stack so we can use this later PHA AND #%00000111 \ Set A = bits 0-2 of A (so that's bits 2-4 of w2_hi) CMP #3 \ If A >= 3, jump to TT205 to skip the first adjective, BCS TT205 ADC #227 \ Otherwise A = 0, 1 or 2, so print recursive token JSR spc \ 67 + A, followed by a space, so: \ \ A = 0 prints token 67 ("LARGE") and a space \ A = 1 prints token 67 ("FIERCE") and a space \ A = 2 prints token 67 ("SMALL") and a space .TT205 PLA \ Now for the second adjective, so restore A to bits LSR A \ 2-7 of w2_hi, and throw away bits 2-4 to leave LSR A \ A = bits 5-7 of w2_hi LSR A CMP #6 \ If A >= 6, jump to TT206 to skip the second adjective BCS TT206 ADC #230 \ Otherwise A = 0 to 5, so print recursive token JSR spc \ 70 + A, followed by a space, so: \ \ A = 0 prints token 70 ("GREEN") and a space \ A = 1 prints token 71 ("RED") and a space \ A = 2 prints token 72 ("YELLOW") and a space \ A = 3 prints token 73 ("BLUE") and a space \ A = 4 prints token 74 ("BLACK") and a space \ A = 5 prints token 75 ("HARMLESS") and a space .TT206 LDA QQ15+3 \ Now for the third adjective, so EOR the high bytes of EOR QQ15+1 \ w0 and w1 and extract bits 0-2 of the result: AND #%00000111 \ STA QQ19 \ A = (w0_hi EOR w1_hi) AND %111 \ \ storing the result in QQ19 so we can use it later CMP #6 \ If A >= 6, jump to TT207 to skip the third adjective BCS TT207 ADC #236 \ Otherwise A = 0 to 5, so print recursive token JSR spc \ 76 + A, followed by a space, so: \ \ A = 0 prints token 76 ("SLIMY") and a space \ A = 1 prints token 77 ("BUG-EYED") and a space \ A = 2 prints token 78 ("HORNED") and a space \ A = 3 prints token 79 ("BONY") and a space \ A = 4 prints token 80 ("FAT") and a space \ A = 5 prints token 81 ("FURRY") and a space .TT207 LDA QQ15+5 \ Now for the actual species, so take bits 0-1 of AND #%00000011 \ w2_hi, add this to the value of A that we used for CLC \ the third adjective, and take bits 0-2 of the result ADC QQ19 AND #%00000111 ADC #242 \ A = 0 to 7, so print recursive token 82 + A, so: JSR TT27 \ \ A = 0 prints token 76 ("RODENT") \ A = 1 prints token 76 ("FROG") \ A = 2 prints token 76 ("LIZARD") \ A = 3 prints token 76 ("LOBSTER") \ A = 4 prints token 76 ("BIRD") \ A = 5 prints token 76 ("HUMANOID") \ A = 6 prints token 76 ("FELINE") \ A = 7 prints token 76 ("INSECT") .TT76 LDA #'S' \ Print an "S" to pluralise the species JSR TT27 LDA #')' \ And finally, print a closing bracket, followed by a JSR TT60 \ paragraph break and Sentence Case, to end the species \ section LDA #193 \ Print recursive token 33 ("GROSS PRODUCTIVITY"), JSR TT68 \ followed by colon LDX QQ7 \ Fetch the 16-bit productivity value from QQ7 into LDY QQ7+1 \ (Y X) JSR pr6 \ Print (Y X) to 5 digits with no decimal point JSR TT162 \ Print a space LDA #0 \ Set QQ17 = 0 to switch to ALL CAPS STA QQ17 LDA #'M' \ Print "M" JSR TT27 LDA #226 \ Print recursive token 66 (" CR"), followed by a JSR TT60 \ paragraph break and Sentence Case LDA #250 \ Print recursive token 90 ("AVERAGE RADIUS"), followed JSR TT68 \ by a colon \ The average radius is calculated like this: \ \ ((w2_hi AND %1111) + 11) * 256 + w1_hi \ \ or, in terms of memory locations: \ \ ((QQ15+5 AND %1111) + 11) * 256 + QQ15+3 \ \ Because the multiplication is by 256, this is the \ same as saying a 16-bit number, with high byte: \ \ (QQ15+5 AND %1111) + 11 \ \ and low byte: \ \ QQ15+3 \ \ so we can set this up in (Y X) and call the pr5 \ routine to print it out LDA QQ15+5 \ Set A = QQ15+5 LDX QQ15+3 \ Set X = QQ15+3 AND #%00001111 \ Set Y = (A AND %1111) + 11 CLC ADC #11 TAY JSR pr5 \ Print (Y X) to 5 digits, not including a decimal \ point, as the C flag will be clear (as the maximum \ radius will always fit into 16 bits) JSR TT162 \ Print a space LDA #'k' \ Print "km", returning from the subroutine using a JSR TT26 \ tail call LDA #'m' JMP TT26