;;==========================================================================;; ;; Joe Zbiciak's GRAM-based Scrolling Demo #2: Large Squares ;; ;; Copyright 2002, Joe Zbiciak, im14u2c AT primenet DOT com. ;; ;; http://www.primenet.com/~im14u2c/intv/ ;; ;;==========================================================================;; ;* ======================================================================== *; ;* TO BUILD IN BIN+CFG FORMAT: *; ;* as1600 -o gram_scroll2.bin -l gram_scroll2.lst gram_scroll2.asm *; ;* *; ;* TO BUILD IN ROM FORMAT: *; ;* as1600 -o gram_scroll2.rom -l gram_scroll2.lst gram_scroll2.asm *; ;* ======================================================================== *; ROMW 16 ; Use 16-bit ROM ;------------------------------------------------------------------------------ ; Include system information ;------------------------------------------------------------------------------ INCLUDE "../library/gimini.asm" ;------------------------------------------------------------------------------ ; Declare variable in scratch (8-bit) and system (16-bit) RAM ; The "-RWBN" specifies that the Intellicart should not map this region. ;------------------------------------------------------------------------------ SCRATCHRAM ORG $100, $100, "-RWBN" ; declare vars in scratch RAM ISRVEC RMB 2 _EOSCRATCH EQU $ SYSTEMRAM ORG $2F0, $2F0, "-RWBN" ; declare vars in system RAM STACK RMB 32 ; reserve 32 words for stack XVEL RMB 1 YVEL RMB 1 XPOS RMB 1 YPOS RMB 1 RNDLO RMB 1 RNDHI RMB 1 _EOSYSTEM EQU $ ORG $5000 ; Use default memory map ;------------------------------------------------------------------------------ ; EXEC-friendly ROM header. ;------------------------------------------------------------------------------ ROMHDR: BIDECLE ZERO ; MOB picture base (points to NULL list) BIDECLE ZERO ; Process table (points to NULL list) BIDECLE INIT ; Program start address BIDECLE ZERO ; Bkgnd picture base (points to NULL list) BIDECLE ONES ; GRAM pictures (points to NULL list) BIDECLE TITLE ; Cartridge title/date DECLE $03C0 ; No ECS title, run code after title, ; ... no clicks ZERO: DECLE $0000 ; Screen border control DECLE $0000 ; 0 = color stack, 1 = f/b mode ONES: DECLE C_BLU, C_BLU ; Initial color stack 0 and 1: Blue DECLE C_BLU, C_BLU ; Initial color stack 2 and 3: Blue DECLE C_BLU ; Initial border color: Blue ;------------------------------------------------------------------------------ ;; ======================================================================== ;; ;; TITLE -- Display our modified title screen & copyright date. ;; ;; ======================================================================== ;; TITLE: PROC BYTE 102, 'GRAM Scroll #2', 0 BEGIN ; Patch the title string to say '=JRMZ=' instead of Mattel. CALL PRINT.FLS ; Write string (ptr in R5) DECLE C_WHT, $23D ; White, Point to 'Mattel' in top-left STRING '=JRMZ=' ; Guess who? :-) STRING ' Productions' BYTE 0 CALL PRINT.FLS ; Write string (ptr in R1) DECLE C_WHT, $2D0 ; White, Point to 'Mattel' in lower-right STRING '2002 =JRMZ=' ; Guess who? :-) BYTE 0 ; Done. RETURN ; Return to EXEC for title screen display ENDP ;;==========================================================================;; ;; INIT -- initialize the main program ;; ;;==========================================================================;; INIT: PROC ; Set the ISR to the rest of our initialization MVII #MAIN, R0 ;\ MVO R0, ISRVEC ; |_ Continue initialization inside SWAP R0 ; | MAIN when the first interrupt MVO R0, ISRVEC+1 ;/ happens. EIS @@spin: DECR PC ENDP ;;==========================================================================;; ;; MAIN -- The main program ;; ;;==========================================================================;; MAIN: PROC ; ============================================================= ; ; Set up everything, and jettison EXEC support. ; ; ============================================================= ; DIS MVII #STACK, R6 ; ------------------------------------------------------------- ; ; Clear the screen to black and enable the display. ; ; ------------------------------------------------------------- ; MVO R0, $20 CLRR R0 MVO R0, $28 MVO R0, $29 MVO R0, $2A MVO R0, $2B MVO R0, $2C ; ------------------------------------------------------------- ; ; Initialize random number generator from contents of RAM. ; ; ------------------------------------------------------------- ; MVII #$100, R4 MVII #$130, R3 @@rnd: ADD@ R4, R0 ADD@ R4, R1 DECR R3 BNEQ @@rnd TSTR R0 BNEQ @@r0_ok MOVR PC, R0 @@r0_ok: TSTR R1 BNEQ @@r1_ok MOVR PC, R1 @@r1_ok: MVO R0, RNDLO MVO R1, RNDHI ; ------------------------------------------------------------- ; ; Set up the interrupt service routine. ; ; ------------------------------------------------------------- ; MVII #ISR, R0 MVO R0, ISRVEC SWAP R0 MVO R0, ISRVEC+1 ; ------------------------------------------------------------- ; ; Fill the screen with the grid. ; ; ------------------------------------------------------------- ; MVII #$801, R0 MVII #$200, R4 CALL FILL_QUAD MVII #$809, R0 MVII #$200 + 20, R4 CALL FILL_QUAD MVII #$811, R0 MVII #$201, R4 CALL FILL_QUAD MVII #$819, R0 MVII #$201 + 20, R4 CALL FILL_QUAD CALL PRINT.FLS DECLE X_GRN, $200 + 6*20 + 3 STRING "GRAM Scrolling", 0 MVII #$811, R0 MVO R0, $200 + 6*20 + 7 ; ------------------------------------------------------------- ; ; Initial scroll velocity is 0.0 for both X and Y. ; ; ------------------------------------------------------------- ; CLRR R0 MVO R0, XVEL MVO R0, YVEL EIS ; ============================================================= ; ; MAIN LOOP ; ; -- Display current velocity and "position". ; ; -- Cycle the random number generator. ; ; Everything else happens in the ISR. ; ; ============================================================= ; @@loop: MVI XVEL, R0 MVII #C_YEL, R1 MVII #$200, R4 CALL HEX16 MVI YVEL, R0 MVII #C_YEL, R1 MVII #$205, R4 CALL HEX16 MVI XPOS, R0 MVII #C_YEL, R1 MVII #$20A, R4 CALL HEX16 MVI YPOS, R0 MVII #C_YEL, R1 MVII #$20F, R4 CALL HEX16 MVII #$10, R2 @@rloop: MVII #$10, R0 CALL RAND DECR R2 BNEQ @@rloop B @@loop ENDP ;; ======================================================================== ;; ;; FILL_QUAD -- Writes to 1 corner of a 4x4 tile of cards. ;; ;; ======================================================================== ;; FILL_QUAD PROC MVII #6, R3 @@l2: MVII #10, R2 @@l1: MVO@ R0, R4 INCR R4 DECR R2 BNEQ @@l1 ADDI #20, R4 DECR R3 BNEQ @@l2 JR R5 ENDP ;; ======================================================================== ;; ;; SHIFT_DAT ;; ;; This array just contains 1 SHL x, for 0 <= x <= 15. ;; ;; ======================================================================== ;; SHIFT_DAT PROC DECLE 0000000000000001b DECLE 0000000000000010b DECLE 0000000000000100b DECLE 0000000000001000b DECLE 0000000000010000b DECLE 0000000000100000b DECLE 0000000001000000b DECLE 0000000010000000b DECLE 0000000100000000b DECLE 0000001000000000b DECLE 0000010000000000b DECLE 0000100000000000b DECLE 0001000000000000b DECLE 0010000000000000b DECLE 0100000000000000b DECLE 1000000000000000b ENDP ;; ======================================================================== ;; ;; ISR ;; ;; This is where all the magic happens. ;; ;; -- Update the horizontal and vertical velocities randomly ;; ;; -- Update our horizontal and vertical positions ;; ;; -- Update the GRAM picture based on the horiz/vert position. ;; ;; ======================================================================== ;; ISR PROC PSHR R5 ; ============================================================= ; ; Make sure display is enabled. ; ; ============================================================= ; MVO R0, $20 ; ============================================================= ; ; Update our X velocity. Clamp the velocity to +/- 512. ; ; ============================================================= ; MVI XVEL, R1 MVI RNDLO, R0 MOVR R0, R3 ; ------------------------------------------------------------- ; ; Take the four LSBs of the random number as our X update. ; ; Bit 0 determines + or -, bits 1 - 3 add to the XVEL. ; ; ------------------------------------------------------------- ; SARC R0, 1 ANDI #7, R0 BNC @@n0 NEGR R0 @@n0: ADDR R0, R1 ; ------------------------------------------------------------- ; ; Clamp to +/- 512 range. ; ; ------------------------------------------------------------- ; CMPI #$01FF, R1 BLT @@okx1 MVII #$01FF, R1 B @@okx @@okx1: CMPI #$FE00, R1 BGT @@okx MVII #$FE00, R1 @@okx: MVO R1, XVEL ; ============================================================= ; ; Update our Y velocity. Clamp the velocity to +/- 512. ; ; ============================================================= ; MVI YVEL, R2 ; ------------------------------------------------------------- ; ; Take the next four bits of the random number as our Y ; ; update. Bit 4 determines + or -, bits 5 - 7 add to the ; ; YVEL. ; ; ------------------------------------------------------------- ; SLR R3, 2 SLR R3, 2 SARC R3, 1 ANDI #7, R3 BNC @@n1 NEGR R3 @@n1: ADDR R3, R2 ; ------------------------------------------------------------- ; ; Clamp to +/- 512 range. ; ; ------------------------------------------------------------- ; CMPI #$01FF, R2 BLT @@oky1 MVII #$01FF, R2 B @@oky @@oky1 CMPI #$FE00, R2 BGT @@oky MVII #$FE00, R2 @@oky: MVO R2, YVEL ; ============================================================= ; ; Update our position based on velocity. ; ; ============================================================= ; ADD XPOS, R1 MVO R1, XPOS ADD YPOS, R2 MVO R2, YPOS ; ============================================================= ; ; The lower byte of the position is our "fraction." The ; ; upper byte gives us the integer portion of the position. ; ; We look at the 4 LSBs of the integer to determine the H and ; ; V offset. ; ; ============================================================= ; SWAP R1, 1 ANDI #15, R1 ; Horizontal offset 0..15 SWAP R2, 1 ANDI #15, R2 ; Vertical offset 0..15 ; ============================================================= ; ; Generate pictures in GRAM that reflect our new offsets. ; ; ============================================================= ; ADDI #SHIFT_DAT, R1 ; Get shifted pixel for column MVI@ R1, R0 ; MVII #$FF, R1 ; Horizontal bar MVII #$3810, R4 ; Point to GRAM cards #2 and #3. MVO@ R0, R4 ; \ MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | NOP ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; |-- Draw right 8 pixels of column NOP ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | NOP ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; / SUBR R2, R4 ; \__ Rewind to draw solid row. DECR R4 ; / MVO@ R1, R4 ; Draw solid row SWAP R0 ; prepare to draw left 8 columns MVII #$3800, R4 ; Point to GRAM cards #0 and #1. MVO@ R0, R4 ; \ MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | NOP ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; |-- Draw left 8 pixels of column NOP ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | NOP ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; | MVO@ R0, R4 ; / SUBR R2, R4 ; \__ Rewind to draw solid row. DECR R4 ; / MVO@ R1, R4 ; Draw solid row @@null: PULR PC ENDP ;; ======================================================================== ;; ;; LIBRARY INCLUDES ;; ;; ======================================================================== ;; INCLUDE "../library/print.asm" ; PRINT.xxx routines INCLUDE "../library/rand.asm" ; RAND routine INCLUDE "../library/fillmem.asm" ; CLRSCR/FILLZERO/FILLMEM INCLUDE "../library/hex16.asm" ; HEX16 ;* ======================================================================== *; ;* This program is free software; you can redistribute it and/or modify *; ;* it under the terms of the GNU General Public License as published by *; ;* the Free Software Foundation; either version 2 of the License, or *; ;* (at your option) any later version. *; ;* *; ;* This program is distributed in the hope that it will be useful, *; ;* but WITHOUT ANY WARRANTY; without even the implied warranty of *; ;* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *; ;* General Public License for more details. *; ;* *; ;* You should have received a copy of the GNU General Public License *; ;* along with this program; if not, write to the Free Software *; ;* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. *; ;* ======================================================================== *; ;* Copyright (c) 2002, Joseph Zbiciak *; ;* ======================================================================== *;