Time to fail for another hour at assembly language…\u00a0 Yesterday I think the routines for writing to the console were tripping me up, so I’m going to start a new file with none of that and just write to port 0 for starters.<\/p>\n
So that ‘worked’ and is predictable in terms of the # of shifts.\u00a0 Note though that CP\/M call 0 ends up wiping what’s on the output (or maybe only port 0 ?)<\/p>\n
For now, I’m not going to worry about getting input – I’m just going to hard code some EQU’s that would eventually be values passed to the routine by something else.<\/p>\n
HOORAY. it works.<\/p>\n
\u00a0<\/p>\n
\u00a0<\/p>\n\n
BITNM\tEQU\t5<\/span>\t\t;THE BIT WERE GOING TO SET (PRESCALER)\nWORD\tEQU\t0<\/span>\t\t;EMPTY<\/span> WORD\nTIMER0\tEQU\t40<\/span>H\t\t;WHERE TO SEND THE WORD\n\n; REAL SIMPLE NOW - FOR<\/span> STARTERS, WE PASS THE WORD & THE BIT TO THE \n; ROUTINE, AND<\/span> IT WILL SET THAT SPECIFIED BIT, AND<\/span> PUT IT ON PORT 0<\/span>\n; REGISTER C WILL BE THE COUNTER\n\nSTART:\tLD\tSP,STACK\t;SETUP STACK POINTER \t\n\n\tLD\tC,BITNM\t\t\n\tLD\tB,WORD\n\tCALL\tSETBIT\n\tLD\tC,0<\/span>\n\tOUT\t(C),A\n\tHALT \n\nSETBIT: PUSH\tBC\t\t;SAVE REGISTERS\t\t\n\tPUSH\tDE\n\tPUSH \tHL\n\tLD\tA,1<\/span>\nRTAT:\tRLCA \t\t\t\t\n\tDEC\tC\n\tJR\tNZ,RTAT\n\tOR<\/span>\tB\n\tPOP\tHL\n\tPOP\tDE\n\tPOP\tBC\n\tRET\n<\/code><\/div>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>","protected":false},"excerpt":{"rendered":"Time to fail for another hour at assembly language…\u00a0 Yesterday I think the routines for writing to the console were tripping me up, so I’m going to start a new file with none of that and just write to port … Continue reading