Anachronaut
992e44ca12
Changed PSHP and POPP into CALL and RET, streamlining their use for subroutine calls. Updated Assembler and Emulator. New demonstration programs.
61 lines
2.3 KiB
NASM
61 lines
2.3 KiB
NASM
; print.asm
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; Some simple SplitBit subroutines for printing.
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; Anachronaut
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; 10/27/2024
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#Program
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BRI Start ; Branch immediately to the start of the program.
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printString:
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CALL saveRegisters ; Store the registers so we can restore them later.
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printLoop:
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LDA ; Move the first character of the string into A.
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BRA Return ; If A is NULL, the string is finished, so return.
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OUTA 0x00 ; Output the character.
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INCD ; Increment Data Pointer to the next character.
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BRI printLoop ; Branch to the beginning of the loop.
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lineFeed:
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CALL saveRegisters ; Save the registers so they can be restored.
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INIA 0x0A ; Load the character for linefeed into A.
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OUTA 0x00 ; Output it.
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CALL restoreRegisters
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BRI Return ; We're done.
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saveRegisters: ; Subroutine for storing the registers.
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PSHD ; Store the Data Pointer, push it to the stack.
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SETD Registers ; Set the Data Pointer to the address for the registers.
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STQ ; Store Q.
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INCD ; Move to the next address.
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STA ; Store A.
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INCD ; Move to the next address.
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STB ; Store B.
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INCD ; Move to the next address.
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POPD ; Restore the Data Pointer.
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RET ; Return to the caller.
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restoreRegisters:
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PSHD ; Save the Data Pointer.
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SETD Registers ; Set the Data Pointer to the registers address.
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RSTB ; Set B to 0.
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LDA ; Load the value for Q into A.
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ADD ; Add 0 to move the value to Q.
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INCD ; Move to the next register value.
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LDA ; Load A with its value.
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INCD ; Move to the next register value.
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LDB ; Load B with its value.
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POPD ; Restore the Data Pointer.
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RET ; Return to the caller.
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Return:
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CALL restoreRegisters ; Restore the registers.
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RET ; Return to the caller.
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#Data
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Registers: ; This is where saveRegisters stores the registers temporarily.
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0x00 ; Q Register
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0x00 ; A Register
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0x00 ; B Register
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