ZXNet эхоконференция «hardware.zx»

============================================================================= * Forwarded by Kirill Frolov (2:5030/946.25) * Area : RU.PHREAKS (Unknown area) * From : Ivanov Arthur - lead.engineer, 2:5020/400 (24 Mar 00 20:58) * To : All * Subj : Трактат об эмуляторах (3 from 3) ============================================================================= From: "Ivanov Arthur - lead.engineer" ;SECOND GENERATION PAYPHONE CARD'S EMULATOR ;Variant 1 - optimized but incorrect a little ;Assumed that real payphone does not try ;to fuse an unit cell fused already ;Intel 87C49 (Quartz - 11 MHz) ;External power supply /battery card/ ;T0 - Clk It is an example ;T1 - Reset how one can implement things ;P1.0 - Out on a really wrong platform ! /smile/ Start: mov r0,#28h-1 Units2RAM: mov a,r0 ; Units data are placed in RAM [0]..[27h] movp3 a,@a ; At the same time [0] and [1] are being mov @r0,a ; used as a work registers r0 and r1 djnz r0,Units2RAM ; r0 ( [0] ) is equal to 0 after djnz Reset: orl p1,#1 mov r0,#0c0h jt1 $ MainLoop: jt1 RstHigh jnt0 MainLoop Read: inc r0 mov a,r0 movp3 a,@a jb1 StaticData mov a,@r0 ; r0 = 0 then refers to itself StaticData: outl p1,a Failure: jt0 $ jmp MainLoop RstHigh: jt0 Reset jt1 RstHigh jnt0 $ Write: mov a,r0 jb7 Failure ;Avoiding an emulator detection in real payphone anl p1,#0feh inc @r0 jt0 $ jt0 Read jnt1 $-2 RstHigh_2: jt0 Reset jt1 RstHigh_2 jnt0 $ WriteCarry: mov a,r0 anl a,#0f8h ; a.0 is clear add a,#8 mov r1,a ; r1.0 is clear too inc @r1 inc r1 inc @r1 inc r1 inc @r1 inc r1 inc @r1 inc r1 inc @r1 inc r1 inc @r1 inc r1 inc @r1 inc r1 ; and now r1.0 ( [1].0 ) is clear after 8 inc inc @r1 jt0 $ jmp MainLoop org 5fh db 0dh,0ah db 0dh,0ah db '+---------------------------+