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Diffstat (limited to 'test/99-WozMon')
| -rw-r--r-- | test/99-WozMon | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/test/99-WozMon b/test/99-WozMon new file mode 100644 index 0000000..2ddbb24 --- /dev/null +++ b/test/99-WozMon @@ -0,0 +1,260 @@ +;------------------------------------------------------------------------- +; +; The WOZ Monitor for the Apple 1 +; Written by Steve Wozniak 1976 +; +;------------------------------------------------------------------------- + + .CR 6502 + .OR $FF00 + .TF WOZMON.HEX,HEX,8 + +;------------------------------------------------------------------------- +; Memory declaration +;------------------------------------------------------------------------- + +XAML .EQ $24 Last "opened" location Low +XAMH .EQ $25 Last "opened" location High +STL .EQ $26 Store address Low +STH .EQ $27 Store address High +L .EQ $28 Hex value parsing Low +H .EQ $29 Hex value parsing High +YSAV .EQ $2A Used to see if hex value is given +MODE .EQ $2B $00=XAM, $7F=STOR, $AE=BLOCK XAM + +IN .EQ $0200,$027F Input buffer + +KBD .EQ $D010 PIA.A keyboard input +KBDCR .EQ $D011 PIA.A keyboard control register +DSP .EQ $D012 PIA.B display output register +DSPCR .EQ $D013 PIA.B display control register + +; KBD b7..b0 are inputs, b6..b0 is ASCII input, b7 is constant high +; Programmed to respond to low to high KBD strobe +; DSP b6..b0 are outputs, b7 is input +; CB2 goes low when data is written, returns high when CB1 goes high +; Interrupts are enabled, though not used. KBD can be jumpered to IRQ, +; whereas DSP can be jumpered to NMI. + +;------------------------------------------------------------------------- +; Constants +;------------------------------------------------------------------------- + +BS .EQ $DF Backspace key, arrow left key +CR .EQ $8D Carriage Return +ESC .EQ $9B ESC key +PROMPT .EQ "\" Prompt character + +;------------------------------------------------------------------------- +; Let's get started +; +; Remark the RESET routine is only to be entered by asserting the RESET +; line of the system. This ensures that the data direction registers +; are selected. +;------------------------------------------------------------------------- + +RESET CLD Clear decimal arithmetic mode + CLI + LDY #%0111.1111 Mask for DSP data direction reg + STY DSP (DDR mode is assumed after reset) + LDA #%1010.0111 KBD and DSP control register mask + STA KBDCR Enable interrupts, set CA1, CB1 for + STA DSPCR positive edge sense/output mode. + +; Program falls through to the GETLINE routine to save some program bytes +; Please note that Y still holds $7F, which will cause an automatic Escape + +;------------------------------------------------------------------------- +; The GETLINE process +;------------------------------------------------------------------------- + +NOTCR CMP #BS Backspace key? + BEQ BACKSPACE Yes + CMP #ESC ESC? + BEQ ESCAPE Yes + INY Advance text index + BPL NEXTCHAR Auto ESC if line longer than 127 + +ESCAPE LDA #PROMPT Print prompt character + JSR ECHO Output it. + +GETLINE LDA #CR Send CR + JSR ECHO + + LDY #0+1 Start a new input line +BACKSPACE DEY Backup text index + BMI GETLINE Oops, line's empty, reinitialize + +NEXTCHAR LDA KBDCR Wait for key press + BPL NEXTCHAR No key yet! + LDA KBD Load character. B7 should be '1' + STA IN,Y Add to text buffer + JSR ECHO Display character + CMP #CR + BNE NOTCR It's not CR! + +; Line received, now let's parse it + + LDY #-1 Reset text index + LDA #0 Default mode is XAM + TAX X=0 + +SETSTOR ASL Leaves $7B if setting STOR mode + +SETMODE STA MODE Set mode flags + +BLSKIP INY Advance text index + +NEXTITEM LDA IN,Y Get character + CMP #CR + BEQ GETLINE We're done if it's CR! + CMP #"." + BCC BLSKIP Ignore everything below "."! + BEQ SETMODE Set BLOCK XAM mode ("." = $AE) + CMP #":" + BEQ SETSTOR Set STOR mode! $BA will become $7B + CMP #"R" + BEQ RUN Run the program! Forget the rest + STX L Clear input value (X=0) + STX H + STY YSAV Save Y for comparison + +; Here we're trying to parse a new hex value + +NEXTHEX LDA IN,Y Get character for hex test + EOR #$B0 Map digits to 0-9 + CMP #9+1 Is it a decimal digit? + BCC DIG Yes! + ADC #$88 Map letter "A"-"F" to $FA-FF + CMP #$FA Hex letter? + BCC NOTHEX No! Character not hex + +DIG ASL + ASL Hex digit to MSD of A + ASL + ASL + + LDX #4 Shift count +HEXSHIFT ASL Hex digit left, MSB to carry + ROL L Rotate into LSD + ROL H Rotate into MSD's + DEX Done 4 shifts? + BNE HEXSHIFT No, loop + INY Advance text index + BNE NEXTHEX Always taken + +NOTHEX CPY YSAV Was at least 1 hex digit given? + BEQ ESCAPE No! Ignore all, start from scratch + + BIT MODE Test MODE byte + BVC NOTSTOR B6=0 is STOR, 1 is XAM or BLOCK XAM + +; STOR mode, save LSD of new hex byte + + LDA L LSD's of hex data + STA (STL,X) Store current 'store index'(X=0) + INC STL Increment store index. + BNE NEXTITEM No carry! + INC STH Add carry to 'store index' high +TONEXTITEM JMP NEXTITEM Get next command item. + +;------------------------------------------------------------------------- +; RUN user's program from last opened location +;------------------------------------------------------------------------- + +RUN JMP (XAML) Run user's program + +;------------------------------------------------------------------------- +; We're not in Store mode +;------------------------------------------------------------------------- + +NOTSTOR BMI XAMNEXT B7 = 0 for XAM, 1 for BLOCK XAM + +; We're in XAM mode now + + LDX #2 Copy 2 bytes +SETADR LDA L-1,X Copy hex data to + STA STL-1,X 'store index' + STA XAML-1,X and to 'XAM index' + DEX Next of 2 bytes + BNE SETADR Loop unless X = 0 + +; Print address and data from this address, fall through next BNE. + +NXTPRNT BNE PRDATA NE means no address to print + LDA #CR Print CR first + JSR ECHO + LDA XAMH Output high-order byte of address + JSR PRBYTE + LDA XAML Output low-order byte of address + JSR PRBYTE + LDA #":" Print colon + JSR ECHO + +PRDATA LDA #" " Print space + JSR ECHO + LDA (XAML,X) Get data from address (X=0) + JSR PRBYTE Output it in hex format +XAMNEXT STX MODE 0 -> MODE (XAM mode). + LDA XAML See if there's more to print + CMP L + LDA XAMH + SBC H + BCS TONEXTITEM Not less! No more data to output + + INC XAML Increment 'examine index' + BNE MOD8CHK No carry! + INC XAMH + +MOD8CHK LDA XAML If address MOD 8 = 0 start new line + AND #%0000.0111 + BPL NXTPRNT Always taken. + +;------------------------------------------------------------------------- +; Subroutine to print a byte in A in hex form (destructive) +;------------------------------------------------------------------------- + +PRBYTE PHA Save A for LSD + LSR + LSR + LSR MSD to LSD position + LSR + JSR PRHEX Output hex digit + PLA Restore A + +; Fall through to print hex routine + +;------------------------------------------------------------------------- +; Subroutine to print a hexadecimal digit +;------------------------------------------------------------------------- + +PRHEX AND #%0000.1111 Mask LSD for hex print + ORA #"0" Add "0" + CMP #"9"+1 Is it a decimal digit? + BCC ECHO Yes! output it + ADC #6 Add offset for letter A-F + +; Fall through to print routine + +;------------------------------------------------------------------------- +; Subroutine to print a character to the terminal +;------------------------------------------------------------------------- + +ECHO BIT DSP DA bit (B7) cleared yet? + BMI ECHO No! Wait for display ready + STA DSP Output character. Sets DA + RTS + +;------------------------------------------------------------------------- +; Vector area +;------------------------------------------------------------------------- + + .DA $0000 Unused, what a pity +NMI_VEC .DA $0F00 NMI vector +RESET_VEC .DA RESET RESET vector +IRQ_VEC .DA $0000 IRQ vector + +;------------------------------------------------------------------------- + + .LI OFF + |