Odyssey paper #06 25 февраля 1999

Программирование

Quickly - the fastest procedure for calculating the addresses of the screen to the coordinates and the fastest procedure press the point.

 Quickly
 __________

 (C) Phantom Lord

 Most fastovy in my opinion adresya calculation on two 
coordinates: 

 ; B - X, E - Y

 LD L, B; 4 takts
 LD H, # 66; 7
 LD D, (HL); 7
 EX DE, HL; 4
 LD E, (HL); 7
 INC H; 4
 LD D, (HL); 7 = 40 takts

 Hence the fastest plot:

 ; B - X, E - Y

 LD L, B; 4 takts
 LD H, # 66; 7
 LD D, (HL); 7
 INC H; 4
 LD C, (HL); 7
 EX DE, HL; 4
 LD E, (HL); 7
 INC H; 4
 LD D, (HL); 7
 LD A, (DE); 7
 OR C; 4
 LD (DE), A; 7 = 69 takts

 ORG # 6600

 DB # C0, # C0, # C0, # C0, # C0, # C0, # C0, # C0
 DB # C2, # C2, # C2, # C2, # C2, # C2, # C2, # C2
 ...
 DB # FE, # FE, # FE, # FE, # FE, # FE, # FE, # FE



  To create an address # C000 screen.