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Sam Coupe Sprite Tutorial - Part 3
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; | |
; ----------------------------------------------------------------------------------- | |
; | | | |
; | Program: SAM Coupe Sprites Tutorial 3 | | |
; | Filename: Sprites3.asm | | |
; | Version: 1.1 | | |
; | Date: 12/10/2017 | | |
; | Author: Pete Gallagher - PJG Creations Ltd | | |
; | | | |
; ----------------------------------------------------------------------------------- | |
; | |
ORG 0x8000 ; Store the program in User Address Space | |
DUMP 1,0 ; | |
autoexec ; Automatically Execute the Program | |
; | |
; *********************************************************************************** | |
; * * | |
; * Equates * | |
; * * | |
; *********************************************************************************** | |
; | |
LMPR: EQU 250 ; The Lower Memory Page Register Address | |
HMPR: EQU 251 ; The Higher Memory Page Register Address | |
VMPR: EQU 252 ; The Video Memory Page Register Address | |
JCLSBL: EQU 334 ; The Clear Screen Routine... | |
; ... Set A to 0 to clear the whole screen) (0x14E) | |
JREADKEY: EQU 361 ; The Keyboard Read Routine... | |
; ... Returns with Z Flag set if no key pressed... | |
; ... Otherwise A = Keycode for key pressed | |
; | |
; *********************************************************************************** | |
; * * | |
; * Application Start * | |
; * * | |
; *********************************************************************************** | |
; | |
DI ; Disable Interupts | |
; | |
; Becuase the Stack Pointer lives in Page B, but we're paging the Screen into Pages A and B, | |
; we need to make sure we save the current Stack Pointer location, and create our own location. | |
; We rewrite our program here effectively, by storing it's original location in a holding position. | |
; | |
LD (System_SP+1),SP; Get the Current Stack Pointer Location and Overwrite... | |
; ... the holding value below. | |
; | |
; Get the Current Screen Page and set the LMPR register up so we can write to the screen | |
; | |
IN A,(VMPR) ; Get the VMPR Register, which holds info about... | |
; ... which Page the Screen is Paged Into | |
AND 0b00011110 ; We're only interested in the Screen Page... | |
; ... so mask off everything but the Page Bits... | |
; ... The result will be stored in the A Register | |
OR 0b00100000 ; Set Bit 5 which, when loaded into the LMPR register... | |
; ... will Set the RAM in Page 0 | |
LD (Scr_Page+1),A ; Overwrite the holding value for the Screen Page location... | |
; ... now that we know it | |
; | |
CALL Clear_Screen ; Clear the Screen | |
; | |
LD SP,0xC000 ; Set the Stack Pointer to a location of our choosing | |
; | |
LD A,(Scr_Page+1) ; Get the current Screen Location which we stored earlier | |
OR 0b00100000 ; Set Bit 5 which, when loaded into the LMPR register... | |
; ... will Set the RAM in Page 0 | |
OUT (LMPR),A ; | |
; | |
; All of the above shifting around of the Stack Pointer, allows us to Call routines... | |
; ... Which of course will store their return location on the Stack Pointer... | |
; ... This would've overwritten some of the Screen Page if left unreseolved... | |
; | |
; CALL Wait_For_Key ; Wait for a keypress | |
; | |
; Print a sprite in the top left corner | |
; | |
LD DE,0x0000 ; Point to the Top Left corner of our screen | |
; | |
; Print a Sprite | |
; | |
print_sprite: LD HL,Sprite1_1 ; Set pointer to start of our Sprite | |
LD BC,512 ; Set up loop counter, 16 bytes per Row of a sprite to print | |
; | |
JP Print_Loop1 ; We must skip the first increment here so that we start at 0 | |
; | |
; This is the start of our Sprite Printing Loop | |
; | |
Print_Loop: LD A,E ; | |
ADD 112 ; | |
LD E,A ; | |
INC D ; Set for the Next Row taking account of our x position | |
; | |
; Print the Even Row of the Sprite | |
; | |
Print_Loop1: FOR 16, LDI ; This is a PYZ80 directive which inserts 16 LDI instructions | |
; | |
LD A,E ; | |
ADD 112 ; | |
LD E,A ; Set for the Next Row taking account of our x position | |
; | |
; Print the Odd Row of the Sprite | |
; | |
FOR 16, LDI ; This is a PYZ80 directive which inserts 16 LDI instructions | |
; | |
; LDI Moves the Value at the location pointed to by (HL)... | |
; ... into the location pointed to by (DE)... | |
; ... It then Decrements BC, setting P/V (Parity / Overflow) flag if the BC has reached zero | |
; | |
JP PE, Print_Loop ; Loop until BC = zero (i.e. P/V set) | |
; | |
CALL Wait_For_Key ; | |
; | |
; | |
; We must remember to switch BASIC back into Page 0 | |
; | |
LD A,0x1F ; Set ROM0 back into Page A... | |
OUT (LMPR), A ; ... So that when we try to return to BASIC it all still works! | |
; | |
; Return the System Stack Pointer to it's original location in Bank B somewhere... | |
; | |
System_SP: LD SP,0 ; Place holder for the System Stack Location... | |
; This will be overwritten above once we know it's location | |
EI ; Enable Interupts | |
; | |
; Return back to BASIC | |
; | |
RET ; | |
; | |
; *********************************************************************************** | |
; * * | |
; * Clear the Screen * | |
; * * | |
; *********************************************************************************** | |
; | |
Clear_Screen: XOR A ; Clear the A register, so when passed into clear screen... | |
; ...it clears the whole screen | |
CALL JCLSBL ; Clear the Screen | |
DI ; Disable Interupts | |
RET ; | |
; | |
; *********************************************************************************** | |
; * * | |
; * Wait for a KeyPres * | |
; * * | |
; *********************************************************************************** | |
; | |
Wait_For_Key: PUSH BC ; Save the BC Registers | |
PUSH DE ; Save the DE Registers | |
PUSH HL ; Save the HL Registers | |
LD A,0x1F ; Set for ROM in Page A | |
OUT (LMPR),A ; | |
; | |
Key_Loop: CALL JREADKEY ; Read the Keyboard (Zero if no key) | |
JR Z,Key_Loop ; If no key pressed, then loop | |
; | |
No_Key_Loop: CALL JREADKEY ; Read the Keyboard (Zero if no key) | |
JR NZ,No_Key_Loop ; If key still pressed, then loop | |
; | |
DI ; Disable Interuprts | |
; | |
Scr_Page: LD A,0 ; Place holder for the Screen Page... | |
; ...The 0 will be overwritten above once we know where it is... | |
OUT (LMPR),A ; Page the Screen into the relevant Page | |
POP HL ; Retrieve the HL Registers | |
POP DE ; Retrieve the DE Registers | |
POP BC ; Retrieve the BC Registers | |
RET ; | |
; | |
; *********************************************************************************** | |
; * * | |
; * Sprites * | |
; * * | |
; *********************************************************************************** | |
; | |
Sprite1_1: DEFB 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF | |
Sprite1_2: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_3: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_4: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_5: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_6: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_7: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_8: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_9: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_10: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_11: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_12: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_13: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_14: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_15: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_16: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_17: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_18: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_19: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_20: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_21: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_22: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_23: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_24: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_25: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_26: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_27: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_28: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_29: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_30: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_31: DEFB 0xF4, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x4F | |
Sprite1_32: DEFB 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF |
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