Sim-8800: Altair 8800 Simulator
INTE PROT MEMR INP MI OUT HLTA STACK WO INT D7 D6 D5 D4 D3 D2 D1 D0 A7 A6 A5 A4 A3 A2 A1 A0 A15 HLDA A14 A13 A12 A11 A10 A9 A8 WAIT SENSE SW. Address Data STOP RUN EXAMINE EXAMINE NEXT SINGLE STEP DEPOSIT DEPOSIT NEXT RESET CLR PROTECT AUX UNPROTECT AUX 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 STATUS OFF ON
Switch Board Helper
A15
A14
A13
A12
A11
A10
A09
A08
A07
A06
A05
A04
A03
A02
A01
A00
OFF/ON
STOP
RUN
SINGLE STEP
EXAMINE
EXAMINE-NEXT
DEPOSIT
DEPOSIT-NEXT
RESET
Load Data to Addr #0
Load Data
In HEX string, such as 'c3 00 00'
8080 CPU Status Dump
Memory Dump
Source code
Quick Tutorial

  • How to input and run the following program to calculate 1 + 2 = 3:

        LDA 0080H  ; 00 111 010
                   ; 10 000 000
                   ; 00 000 000
        MOV B,A    ; 01 000 111
        LDA 0081H  ; 00 111 010
                   ; 10 000 001
                   ; 00 000 000
        ADD B      ; 10 000 000
        STA 0082H  ; 00 110 010
                   ; 10 000 010
                   ; 00 000 000
        JMP 0000H  ; 11 000 011
                   ; 00 000 000
                   ; 00 000 000

  1. Turn on Altair 8800 by clicking OFF/ON switch.
  2. Set switches A7-A0 to 00 111 010 (up for 1, down for 0).
  3. Click "DEPOSIT".
  4. Set switches A7-A0 to 10 000 000.
  5. Click "DEPOSIT NEXT".
  6. Repeat step 4-5 to input the following bytes one by one: 00 000 000, 01 000 111, 00 111 010, 10 000 001, 00 000 000, 10 000 000, 00 110 010, 10 000 010, 00 000 000, 11 000 011, 00 000 000, 00 000 000.
  7. Set switches A7-A0 to 10 000 000.
  8. Click "EXAMINE".
  9. Set switches A7-A0 to 00 000 001 (the first number to be added, or 1 in decimal).
  10. Click "DEPOSIT".
  11. Set switches A7-A0 to 00 000 010 (the second number to be added, or 2 in decimal).
  12. Click "DEPOSIT NEXT".
  13. Click "RESET".
  14. Click "RUN" and wait for a few seconds.
  15. Click "STOP".
  16. Set switches A7-A0 to 10 000 010 (the address that holds the sum).
  17. Click "EXAMINE".
  18. The LEDs D7-D0 show the result 00 000 011 (3 in decimal).
  19. Turn off Altair 8800.

References