Z80 Assembly programming for the Elan Enterprise 128

The Enterprise 128 is an 8 bit Z80 system, it's comparable to the Amstrad CPC,however it has more advanced Memory Mapping which allows more flexible bank switching, and more advanced graphics Like the CPC screen it can function at 320x200 at 4 colors, and you can halve the resolution to get 160x200 with 16 colors... unlike the CPC, there is a 256 color mode of 80x200 All these modes can be 'half resolution' of 100 vertical pixels

The Basic Enterprise has 64k, but we'll be focusing on the 256k version Cpu 4 mhz Z80 Ram 64k / 128k Resolution 320x200 4 color 160x200 16 color 80x200 256 color Sound chip 3 Channel sound (non AY)

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The Enterprise screen memory location and layout is defined by a LPT block

write "..\RelEnt\program.com" ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;            Hello World ; ;    Show a hello world message, then read a key ;    From the keyboard and show it. ; ;    Screen and keyboard ops use Enterprise OS calls ;    by opening 'stream' devices to the Keyboard and ;    screen ; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ORG &00F0     DB 0,5               ;type 5 - Binary Program     DW FileEnd-FileStart       ;File length     DB 0,0,0,0,0,0,0,0,0,0,0,0 ;Spacer ; org &0100 FileStart:     LD SP,&100    ;set the Stack to a safe place     di     ld c,MODE_VID        ;Set text mode     ld d,0     call ENT_Writevar     ld c,COLR_VID        ;Set 2 color     ld d,0     call ENT_Writevar     ld c,X_SIZ_VID        ; 40 Chars Wide     ld d,40     call ENT_Writevar     ld c,Y_SIZ_VID        ;24 chars tall     ld d,24     call ENT_Writevar     ld de,ENT_Screenname     ;Open Screen as stream 10     ld a,10     call ENT_OpenStream         ;Display the just opened screen     ld a,10    ; A channel number (1..255)     ld b,1    ; B @@DISP (=1) (special function code)     ld c,1    ; C 1st row in page to display (1..size)     ld d,24  ; D number of rows to display (1..27)     ld e,1  ; E row on screen where first row should appear (1..27)     call ENT_SpecialFunc     ld de,ENT_Keboardname    ; Open the keyboard as stream 11     ld a,11     call ENT_OpenStream ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;            INIT Done ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;     ld hl,Message     call PrintString    ;Print Hello world message     call NewLine             call WaitChar        ;Wait for a keypress     push af         ld hl,Message2    ;Print 'You Pressed' message         call PrintString     pop af     call PrintChar        ;print the char the user pressed     call NewLine     di     halt    ;stop execution - I've not figured out how to return to basic! Message: db 'Hello World!',255 Message2: db 'Key Pressed:',255 PrintString:     ld a,(hl)     cp 255     ret z     inc hl     call PrintChar jr PrintString ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;        Functions for controling EXOS ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; MODE_VID  equ 22    ;Enterprise OS variable numbers COLR_VID  equ 23 X_SIZ_VID equ 24 Y_SIZ_VID equ 25     ENT_OpenStream:     ;Open stream A from device string DE     ;DE should point to a string like...  db 6,'VIDEO;'  or db 9,'KEYBOARD;' (replace ; with a colon)     rst 6     db 1     ;open stream ret WaitChar:     push de     push hl     push bc         ld a,11         rst 6         db 5     ;read from channel - result in b         ld a,b     pop bc     pop hl     pop de ret PrintChar:     push de     push hl     push bc         ld b,a         ld a,10         rst 6         db 7     ;write to channel a     pop bc     pop hl     pop de ret NewLine:     ld a,13     call PrintChar     ld a,10     call PrintChar ret ENT_readvar:        ;readvar C from enterprise OS     ld b,0     rst 6     db 16 ret ENT_Writevar:        ;WriteVar C=D to Enterprise OS     ld b,1     rst 6     db 16 ret ENT_SpecialFunc:    ;Special Function (for displaying screen)     rst 6     db 11 ret ;Device names db [length],'name;' ENT_Screenname: db 6,'VIDEO:' ENT_Keboardname: db 9,'KEYBOARD:' ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; FileEnd:

Starting the program: The program will show hello world, then pause for a keypress