Language Assembler (Z80)
(Amstrad CPC Version)
Date: | 08/20/05 |
Author: | Duncan Bayne |
URL: | http://dotgeek.blogspot.com/ |
Comments: | 2 |
Info: | http://winape.emuunlim.com/ |
Score: | (3.33 in 244 votes) |
org &a000 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This program prints the '99 bottles of beer' lyrics. It was lovingly ; handcrafted, assembled and tested using the WinAPE Amstrad CPC ; Emulator, version 2.0 Alpha 6. ; ; This program is Free Software, and may be used and redistributed under ; the terms of the GNU LGPL. ; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ld a,&02 call &bc0e; ; set high-res mode for 80-column text ld hl,count ld (hl),&63 ; this is the starting number of bottles .nextbottle ld a,(count) ld hl,str_plural push hl ld a,(count) ld h,&00 ld l,a push hl ld hl,str_plural push hl ld a,(count) ld h,&00 ld l,a push hl ld hl,str_bottles1 push hl call printf ; print the first line ld a,(count) dec a ; decrement the count cp &01 jr nz,notone ld hl,str_plural ; null the plural string if we're down to one bottle ld (hl),&00 .notone cp &00 jr z,finish ld (count),a ld hl,str_plural push hl ld a,(count) ld h,&00 ld l,a push hl ld hl,str_bottles2 push hl call printf ; print the second line jr nextbottle .finish ld hl,str_finish push hl call printf ; print the final three lines ret ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This is a simple version of printf. It works on a null-terminated ; format string, with the following parameter types: ; ; %s null-terminated ASCII string ; %d single-byte unsigned int ; %c ASCII character ; ; The single-byte unsigned int is printed in decimal, with leading ; zeroes dropped. To print single '%' characters, double them up ; (e.g. "%%"). ; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; .printf pop bc pop hl .charloop ld a,(hl) cp &00 jr z,nullterm cp '%' ; this is a parameter jr z,parameter call &bb5a ; this is just a plain ol' ASCII character .nextchar inc hl jr charloop .nullterm push bc ret .parameter inc hl ; get the next char, which is the type ld a,(hl) cp '%' jr z,percent ; a plain '%' character cp 'c' jr z,char ; a single ASCII character cp 's' jr z,string ; a string cp 'd' jr z,number ; a number (8-bit) .string pop de ; print a simple null-terminated string .nextcharstring ld a,(de) cp &00 jr z,nulltermstring call &bb5a inc de jr nextcharstring .nulltermstring jr nextchar .percent call &bb5a ; it's a simple '%' character jr nextchar .char pop de ; print an ASCII character ld a,e call &bb5a jr nextchar .number pop de push hl ; we'll be needing this later ld a,e ld hl,hundreds ; reset the place counts ld (hl),&00 ld hl,tens ld (hl),&00 ld hl,ones ld (hl),&00 .dohundreds ; count the hundreds in the number ld d,&64 ld hl,hundreds .nexthundred sub d jr c,dotens inc (hl) jr nexthundred .dotens ; count the tens in the number add d ld d,&0a ld hl,tens .nextten sub d jr c,doones inc (hl) jr nextten .doones ; whatever is left is the ones add d ld (ones),a ld d,0 .printhundreds ld a,(hundreds) cp &00 jr z,printtens ; skip leading zeroes add a,&30 ; print the hundreds call &bb5a ld d,1 .printtens ld a,(tens) add d cp &00 jr z,printones ; skip leading zeroes sub d ld d,1 add a,&30 ; print the tens call &bb5a .printones ld a,(ones) add a,&30 ; print the ones call &bb5a pop hl ; take hl back off the stack, oh for more registers jp nextchar ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; These are the data used by the program. ; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; .hundreds defb &00 .tens defb &00 .ones defb &00 .str_bottles1 defm "%d bottle%s of beer on the wall, %d bottle%s of beer." defb &0d defb &0a defb &00 .str_bottles2 defm "Take one down and pass it around, %d bottle%s of beer on the wall." defb &0d defb &0a defb &0d defb &0a defb &00 .str_finish defm "Take one down and pass it around, no more bottles of beer on the wall." defb &0d defb &0a defb &0d defb &0a defm "No more bottle of beer on the wall, no more bottles of beer." defb &0d defb &0a defm "Go to the store and buy some more, 99 bottles of beer on the wall." defb &0d defb &0a defb &0d defb &0a .str_plural defm "s" defb &00 .str_single defb &00 .count defb &00
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Alternative Versions
Version | Author | Date | Comments | Rate |
---|---|---|---|---|
Sinclair/Timex variant | Damien Guard | 07/28/05 | 7 | |
2004 submission | Elroy Sullivan & Barry Goode | 08/13/09 | 0 |
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Comments
Duncan Bayne said on 08/22/05 22:27:10
Since I submitted this, a poster to my blog has suggested that I'd be better off implementing a stack-frame parameter passing mechanism, rather than have the callee responsible for the return address and cleaning up the stack.
I think he's right, so (at some stage) I'll be revisiting this code ...
Duncan Bayne said on 07/24/06 05:23:23
Since I posted this implementation, I have closed my DotGeek blog at http://dotgeek.blogspot.com/, and the old URL has been taken over by a spammer :-(
My new blog is at: http://solopassion.com/blog/4.