mirror of
https://github.com/nippur72/apple1-videocard-lib.git
synced 2024-12-23 04:29:46 +00:00
256 lines
8.9 KiB
C
256 lines
8.9 KiB
C
#include <utils.h>
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#include <apple1.h>
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__address(0x24) word ENDADDR; // End address of dump block
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__address(0x26) word STARTADDR; // Begin address of dump block
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__address(0x29) byte LASTSTATE; // Last input state
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__address(0x30) byte NUMPULSES; // Number of long pulses to sync at the header
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__address(0xC081) byte TAPEIN; // Tape input
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__address(0xD012) byte DSP; // display data port
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/*
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#pragma zp_reserve(0x24)
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#pragma zp_reserve(0x25)
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#pragma zp_reserve(0x26)
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#pragma zp_reserve(0x27)
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#pragma zp_reserve(0x29)
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#pragma zp_reserve(0x30)
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__export byte *const ENDADDR = (byte *) 0x24; // End address of dump block
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__export byte *const STARTADDR = (byte *) 0x26; // Begin address of dump block
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__export byte *const LASTSTATE = (byte *) 0x29; // Last input state
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__export byte *const NUMPULSES = (byte *) 0x30; // Number of long pulses to sync at the header
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__export byte *const TAPEIN = (byte *) 0xC081; // Tape input
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__export byte *const DSP = (byte *) 0xD012; // display data port
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*/
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byte PACKETSIZE;
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byte reference_packet[256];
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byte *vmeter = "0123456789ABCDEF";
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//byte *const RX_BUFFER = (byte *) 0x060c; //0x4200;
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const byte RX_BUFFER[256]; // TODO ??????????????????????????????????????????
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void read_packet()
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{
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word RX_BUFFER_END = (word) RX_BUFFER + (word) PACKETSIZE - 1;
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ENDADDR = (word) RX_BUFFER_END;
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STARTADDR = (word) RX_BUFFER;
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/*
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*((word *)ENDADDR) = (word) RX_BUFFER_END;
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*((word *)STARTADDR) = (word) RX_BUFFER;
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*/
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/*
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woz_putc('\r');
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woz_print_hex(*(STARTADDR+1)); woz_print_hex(*(STARTADDR));
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woz_putc('.');
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woz_print_hex(*(ENDADDR+1)); woz_print_hex(*(ENDADDR));
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*/
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asm {
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// synchronizes with the short header
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syncstart: lda #24 // 24 cycles (3 bytes of $ff)
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sta NUMPULSES // count 24 cycles pulses
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jsr fullcycle // skip the first full cycle (when looping)
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nextsync: ldy #58 // full cycle duration
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jsr fullcycle // read a full cycle
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bcc syncstart // if short cycle found (c=0), redo from start
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dec NUMPULSES // else long cycle found, decrease count
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bne nextsync // if not 24 cycles, get next cycle
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// else read bit start and 32 bytes of data normally
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// the following routine was copied directly from the ACI ROM
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notstart: ldy #31 // try to detect the much shorter start bit
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jsr cmplevel //
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bcs notstart // start bit not detected yet!
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jsr cmplevel // wait for 2nd phase of start bit
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ldy #58 // set threshold value in middle
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rdbyte: ldx #8 // receiver 8 bits
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rdbit: pha
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jsr fullcycle // detect a full cycle
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pla
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rol // roll new bit into result
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ldy #57 // set threshold value in middle
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dex // decrement bit counter
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bne rdbit // read next bit!
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sta (STARTADDR,x) // save new byte
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jsr incaddr // increment address
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ldy #53 // compensate threshold with workload
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bcc rdbyte // do next byte if not done yet!
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bcs restidx // always taken! restore parse index
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fullcycle: jsr cmplevel // wait for two level changes
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cmplevel: dey // decrement time counter
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lda TAPEIN // get tape in data
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cmp LASTSTATE // same as before?
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beq cmplevel // yes!
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sta LASTSTATE // save new data
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cpy #128 // compare threshold
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rts
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// [...]
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incaddr: lda <STARTADDR // compare current address with
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cmp <ENDADDR // end address
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lda >STARTADDR
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sbc >ENDADDR // carry set if STARTADDR = ENDADDR
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inc <STARTADDR // increment current address
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bne no_inc_hi //
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inc >STARTADDR
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no_inc_hi: rts
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// end of read routine "restidx" is the exit point
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restidx: rts
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}
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}
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void decode_packets() {
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woz_puts("\rPACKET DECODER MONITOR\r");
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// fill the reference packet with the known values
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for(byte t=0;t<PACKETSIZE;t++) reference_packet[t] = t;
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// tape monitor loop
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for(;;) {
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read_packet(); // attempt reading 1 packet
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// compare received packet with reference
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byte i;
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for(i=0;i<PACKETSIZE;i++) {
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if(RX_BUFFER[i] != reference_packet[i]) break;
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}
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// display result
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if(i==0) woz_putc('.');
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else if(i==PACKETSIZE) woz_putc('*');
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else {
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if(PACKETSIZE == 32) woz_putc(vmeter[i>>1]);
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if(PACKETSIZE == 64) woz_putc(vmeter[i>>2]);
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if(PACKETSIZE == 128) woz_putc(vmeter[i>>3]);
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if(PACKETSIZE == 255) woz_putc(vmeter[i>>4]);
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}
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/*
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if(apple1_readkey()=='D') {
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woz_puts("\r\r");
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for(i=0;i<PACKETSIZE;i++) {
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woz_print_hex(RX_BUFFER[i]); woz_putc(' ');
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}
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}
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*/
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// exit with "X"
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if(apple1_readkey()=='X') break;
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}
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}
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void simple_toggle_monitor()
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{
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woz_puts("\rTAPE BIT TOGGLE MONITOR\r");
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asm {
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simple_monitor: lda TAPEIN // read tape input
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cmp LASTSTATE // compare to previous state
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beq no_toggle // if same just skip
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sta LASTSTATE // else save new state
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ldx #35 // set "toggle detected" flag in X, 35 is also the char to print
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no_toggle: bit DSP // check if display is ready to accept a character
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bmi simple_monitor // if not, just keep reading tape
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stx DSP // else display the "toggle detected" flag character
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ldx #45 // resets the "toggle detected" flag to the "-" sign, sets also Z=0 flag
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bne simple_monitor // cheap jump because Z is also 0
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}
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}
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// store the lengths for each phase
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byte phase0[256];
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byte phase1[256];
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void count_256_phase_lengths() {
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asm {
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ldx #0 // count pulses
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countpulse: ldy #00 // phase length
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lphase0: iny // decrement phase length
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lda TAPEIN // get tape in data
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cmp LASTSTATE // same as before?
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beq lphase0 // yes, keep counting
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sta LASTSTATE // save new state
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tya
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sta phase0,x // save phase0 length
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ldy #00 // phase length
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lphase1: iny // decrement phase length
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lda TAPEIN // get tape in data
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cmp LASTSTATE // same as before?
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beq lphase1 // yes, keep counting
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sta LASTSTATE // save new state
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tya
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sta phase1,x // save phase0 length
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inx
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bne countpulse // if not 256, repeat
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}
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}
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void duty_cycle_monitor() {
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woz_puts("\rDUTY CYCLE MONITOR\r");
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while(1) {
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count_256_phase_lengths();
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// don't consider the first phase, because it's measured during transition
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phase0[0] = phase0[1];
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phase1[0] = phase1[1];
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word sum_0 = 0;
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word sum_1 = 0;
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byte i=0;
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do {
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sum_0 += phase0[i];
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sum_1 += phase1[i];
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i++;
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} while(i!=255);
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// make average
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sum_0 = sum_0 / 256;
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sum_1 = sum_1 / 256;
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// display result in 5 columns
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woz_print_hex((byte)sum_0);
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woz_putc('-');
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woz_print_hex((byte)sum_1);
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woz_puts(" ");
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byte k = apple1_readkey();
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if(k=='X') break;
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}
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}
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void main() {
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while(1) {
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woz_puts("\r\rTAPE MONITOR\r\r"
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"1,2,3,4 => 32,64,128,255 BYTES PACKETS\r"
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"T SIMPLE TOGGLE MONITOR\r"
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"D DUTY CYLE MONITOR\r\r"
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"X EXIT\r\r"
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);
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byte key = apple1_getkey();
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if(key == '1') { PACKETSIZE = 32; decode_packets(); }
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if(key == '2') { PACKETSIZE = 64; decode_packets(); }
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if(key == '3') { PACKETSIZE = 128; decode_packets(); }
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if(key == '4') { PACKETSIZE = 255; decode_packets(); }
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if(key == 'T') simple_toggle_monitor();
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if(key == 'D') duty_cycle_monitor();
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if(key == 'X') woz_mon();
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}
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}
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