Try out xor , GO from 0f22 , code is run and monitor displays result FF.
Some very simple hex to type in to the MK 14. It works out 0xAA xor 0x55 which equals 0x FF. It stores the result in memory just after the return to the monitor.
Z 0F22 T or Z 0F21 M C4 M AA M E4 M 55 M C8 M 02 M 3F ;now go an execute Z 0F22 G ; you should read: 0F29 FF
32 0f22: 33 0f22: ; load accumulator with 0xAA eor with 0x55 and store 34 0f22: c4 aa ldi 0aah 35 0f24: e4 55 xri 055h 36 0f26: 37 0f26: c8 02 st 2 (0) 38 0f28: ; return to the monitor 39 0f28: 3f xppc 3 40 0f29: 41 0f29: 42 0f29: ; next code is overwritten by result.
execute from 0F20. Jmp to routine. set up P1 to point to the display.
load 0xAA and write to display.
31 0f20: 90 00 jmp main0 32 0f22: 33 0f22: main0: 34 0f22: ; reload display pointer. 35 0f22: c4 00 LDI Disp.0 36 0f24: 31 XPAL 1 37 0f25: c4 0d LDI Disp.1 38 0f27: 35 XPAH 1 39 0f28: 40 0f28: c4 aa ldi 0aah 41 0f2a: cd 00 st @0(1) 42 0f2c: 43 0f2c: 90 f4 jmp main0 44 0f2e: 45 0f2e:
86 0f61: main2: 87 0f61: ; reload display pointer. 88 0f61: c4 00 LDI Disp.0 89 0f63: 31 XPAL 1 90 0f64: c4 0d LDI Disp.1 91 0f66: 35 XPAH 1 92 0f67: 93 0f67: ; read keyboard, invert and write to display, increment pointer to next digit 94 0f67: c5 00 ld @0(1) 95 0f69: e4 ff xri 0ffh 96 0f6b: cd 01 st @+1(1) 97 0f6d: 8f 04 dly 4 98 0f6f: 99 0f6f: 100 0f6f: ; read keyboard, invert and write to display, increment pointer to next digit 101 0f6f: c5 00 ld @0(1) 102 0f71: e4 ff xri 0ffh 103 0f73: cd 01 st @+1(1) 104 0f75: 8f 04 dly 4 105 0f77: 106 0f77: ; read keyboard, invert and write to display, increment pointer to next digit 107 0f77: c5 00 ld @0(1) 108 0f79: e4 ff xri 0ffh 109 0f7b: cd 01 st @+1(1) 110 0f7d: 8f 04 dly 4 111 0f7f: 112 0f7f: ; read keyboard, invert and write to display, increment pointer to next digit 113 0f7f: c5 00 ld @0(1) 114 0f81: e4 ff xri 0ffh 115 0f83: cd 01 st @+1(1) 116 0f85: 8f 04 dly 4 117 0f87: 118 0f87: ; read keyboard, invert and write to display, increment pointer to next digit 119 0f87: c5 00 ld @0(1) 120 0f89: e4 ff xri 0ffh 121 0f8b: cd 01 st @+1(1) 122 0f8d: 8f 04 dly 4 123 0f8f: 124 0f8f: ; read keyboard, invert and write to display, increment pointer to next digit 125 0f8f: c5 00 ld @0(1) 126 0f91: e4 ff xri 0ffh 127 0f93: cd 01 st @+1(1) 128 0f95: 8f 04 dly 4 129 0f97: 130 0f97: ; read keyboard, invert and write to display, increment pointer to next digit 131 0f97: c5 00 ld @0(1) 132 0f99: e4 ff xri 0ffh 133 0f9b: cd 01 st @+1(1) 134 0f9d: 8f 04 dly 4 135 0f9f: 136 0f9f: ; read keyboard, invert and write to display, increment pointer to next digit 137 0f9f: c5 00 ld @0(1) 138 0fa1: e4 ff xri 0ffh 139 0fa3: cd 01 st @+1(1) 140 0fa5: 8f 04 dly 4 141 0fa7: 142 0fa7: 143 0fa7: 90 b8 jmp main2 144 0fa9: