Fifth installment of the Z80 machine language series, presenting the world-map printing routine for CONQUEST. Covers FMO (find map start based on player position), PMAP (print map to screen), WRAP (horizontal and vertical wrapping logic for a 64×64 toroidal map), FINDAT (attribute address calculation), and PRUDG (print User Defined Graphic characters for map symbols). Full assembly listings with addresses and mnemonics.
A routine to print a map that wraps in both directions, i.e., go off the map westward puts you on the eastern edge, northward on the southern edge or vise versa. The map itself is 64×64. We have two variables called Mapcox and Mapcoy (stored at 52396/7) which define what map coordinates (starting with 1,1) is being printed in the upper left corner of the screen. Since this routine also prints the player maps, it uses the variable Player (at 31539). The master map is stored at 32000. Each map requires 4096 bytes of space so player 1’s map starts at 36096, etc. We need a special variable called WRAPF (at 52389). The routine is entered at 60475 preceded by PMO which is a routine that finds the correct space in memory to start from.
The Findat routine depends upon how you set the various UDG characters on your map. For Conquest they are: 0 blank, 1 sea, 2 land, 3 mountain, 4 shoal, 5 city, 6-15 units whose color will be yellow, red and white for players 1 to 3 respectively. For cities and units ownership is designated in the top 2 bits.
We are running out of space so we will finish this routine in the next installment.
PLAYEREQU 31539from article prose
WRAPFEQU 52389from article prose
PRUDGEQU 60791printed at this address in issue #6
P1EQU 60726issue #6 resumes the listing here
MAPCOYEQU 52396issue #6 gives MAPCOX as 52397, so 52396 is MAPCOY
60442120PMOLD A,BBC=MAPCOX,MAPCOY
6044361DEC A
6044438,0LD H,0
60446167AND A
6044723RLA
6044823RLA
6044923RLA
60450203,20RL H
6045223RLA
60453203,20RL H
6045523RLA
60456203,20RL H
6045823RLAinserted per the correction in issue #6
60459203,20RL Hinserted per the correction in issue #6
60461111LD L,ATHE RIGHT STARTING POINT OF ANY MAP
6046258,51,123LD A,(PLAYER)
60465167AND A
6046623RLA
6046723RLA
6046823RLA
6046923RLA
60470132ADD A,H
60471198,125ADD A,125ADD THE OFFSET TO MAP ZERO (MASTER)
60473103LD H,A
60474121LD A,C
6047561DEC A
60476133ADD A,L
60477111LD L,A
60478201RET
60479237,75,172,204PMAPLD BC,(MAPCOY)
60483205,26,236CALL PMO
60486175XOR A
6048750,165,204LD (WRAPF),ARESET WRAP FLAG
60490229PUSH HLSAVE HL ADDRESS FOR CALC. ATTR
6049117,0,64LD DE,16384SET DE TO TOP OF SCREEN
604946,3LD B,3WE ARE GOING TO PRINT ALL 24 LINES OF THE SCREEN, NOT JUST THE FIRST 21
60496197NEXTPUSH BCSAVE COUNT
6049714,8LD C,88 LINES
604996,32NEXT1LD B,3232/LINE
60501126NEXT2LD A,(HL)GET USER DEFINED CHARACTER
60502205,119,237CALL PRUDGPRUDG CONVERTS THE CHARACTER CODE TO THE CORRECT SPOT IN THE UDG TABLE AND PRINTS IT TO THE SCREEN
60505205,232,236CALL WRAPTHIS SUBROUTINE DOES THE ACTUAL DETERMINATION OF WHEN WE ARE AT A SEAM AND ADJUSTS HL ACCORDINGLY. A=WRAPF, 0=NO WRAP, 255=WRAP
60508254,255CP 255
6051032,8JR NZ,PM1
60512213PUSH DESAVE POINT ON SCREEN
6051317,64,0LD DE,64
60516167AND A
60517237,82SBC HL,DE
60519209POP DE
6052035PM1INC HLNOW RESET DE
60521122LD A,D
60522214,8SUB 8
6052487LD D,A
6052519INC DE
6052616,229DJNZ NEXT2
60528213PUSH DE
6052958,165,204LD A,(WRAPF)
60532254,0CP 0
6053440,5JR Z,AD-3AT END OF LINE WE HAVE TO ADD EITHER 96 OR 32 TO HL
6053617,96,0LD DE,96
6053924,3JR AD
6054117,32,0LD DE,32
6054425ADADD HL,DE
6054558,51,123LD A,(PLAYER)
60548167AND A
6054923RLA
6055023RLA
6055123RLA
6055223RLA
60553198,141ADD A,141
6055587LD D,A
60556124LD A,H
60557186CP D
6055832,3JR NZ,PM2RESET TO TOP OF MAP
60560214,16SUB 16
60562103LD H,A
60563209PM2POP DE
6056413DEC C
6056532,188JR NZ,NEXT1ADJUST DE TO NEXT SET OF 8
60567122LD A,D
60568198,7ADD A,7
6057087LD D,A
60571193POP BC
6057216,178DJNZ NEXT
60574225POP HL
6057517,0,88LD DE,22528
6057814,24LD C,24
605806,32NEXT3LD B,32
60582197NEXT4PUSH BC
60583126LD A,(HL)
60584205,254,236CALL FINDATTHIS ROUTINE CALCULATES BOTH INK AND PAPER FOR THE CHARACTER AND STORES IT IN A
6058718LD (DE),A
60588205,232,236CALL WRAP
60591254,255CP 255
6059332,8JR NZ,NIX
60595213PUSH DE
6059617,64,0LD DE,64
60599167AND A
60600237,82SBC HL,DE
60602209POP DE
6060319NIXINC DE
6060435INC HL
60605193POP BC
6060616,230DJNZ NEXT4
60608213PUSH DE
6060958,165,204LD A,(WRAPF)
60612254,0CP 0
6061440,5JR Z,A1-3
6061617,96,0LD DE,96
6061924,3JR A1
6062117,32,0LD DE,32
6062425A1ADD HL,DE
6062558,51,123LD A,(PLAYER)
60628167AND A
6062923RLA
6063023RLA
6063123RLA
6063223RLA
60633198,141ADD A,141
6063587LD D,A
60636124LD A,H
60637186CP D
6063832,3JR NZ, PR3
60640216,16SUB 16
60642103LD H,A
60643209PR3POP DE
6064413DEC C
6064532,189JR NZ,NEXT3
60647201RET
60648125WRAPLD A,L
60649254,63CP 63NOTE: 63, 127, 191 AND 255 FOR L INDICATE THE EASTERN EDGE OF THE MAP
6065140,11JR Z,CONT
60653254,127CP 127
6065540,7JR Z,CONT
60657254,191CP 191
6065940,3JR Z,CONT
60661254,255CP 255
60663192RET NZ
6066462,255CONTLD A,255
6066650,165,204LD (WRAPF),A
60669201RET
60670254,0FINDATCP 0
6067232,3JR NZ,AT1
6067462,7LD A,7P=BK,I=W
60676201RET
60677254,1AT1CP 1
6067932,3JR NZ,AT2
6068162,15LD A,15P=BL,I=W
60683201RET
60684254,4AT2CP 4
6068648,3JR NC,AT4
6068862,32LD A,32P=GR,I=BK
60690201RET
60691254,4AT4CP 4
6069332,3JR NZ,AT5
6069562,41LD A,41P=AQ,I=BL
60697201RET
60698254,5AT5CP 5
6070032,3JR NZ,C2
6070262,59LD A,59P=W,I=MG
60704201RET
60705254,69C2CP 69PLAYER1?
6070732,3JR NZ,C3
6070962,48LD A,48P=BK,I=Y
60711201RET
60712254,133C3CP 133PLAYER2?
6071432,3JR NZ,C4
6071662,16LD A,16P=BK,I=R
60718201RET
60719254,197CP 197PLAYER3?
6072132,3JR NZ,P1
6072362,56LD A,56P=BK,I=W
60725201RETprinted at 60721 in issue #5; two bytes at the previous line put it here
