Port of the C64 game 1nvader for the PDP-1 computer from 1959, written in macro1 assembly.
To build on Windows just run the make.bat file, which will join the source files, assemble using macro1.exe, convert the binary to a base64 string and then insert it into the .js file that the emulator uses as a pretend paper-tape, then launch the html file.
For mac/linux you'll need to build macro.c that's in the cmd folder and convert the .bat file to an .sh file.
To use with other PDP-1 emulators or even the real thing (!) the binary file is called main.rim and is in the build folder.
While I was learning the instruction set I put together this table that explains the most important instructions and where there is a 6502 equivalent or near-equivalent:
| Load and Store | 6502 | Description | Notes |
|---|---|---|---|
| lac | lda | Load Accumulator with Y | |
| law | lda | Load Accumulator with N | Load immediate |
| dac | sta | Deposit Accumulator into Y | Store to memory |
| dap | Deposit Address Part into Y | Self-mod address of instruction | |
| dip | Deposit Instruction Part into Y | Self-mod op code of instruction | |
| lio | ldx | Load In-Out Register from Y | |
| dio | stx | Deposit In-Out Register to Y | |
| dzm | Deposit Zero to Y | Clear memory address | |
| lap | Transfer PC to A | ||
| cla | Clear Accumulator | ||
| cli | Clear IO |
| Mathematical Operations | 6502 | Description | Notes |
|---|---|---|---|
| add | adc | Add Y to A | |
| sub | sbc | Minus Y from A | |
| mul | Multiply A and Y into A and IO | ||
| div | Divide AC/IO by Y, quotient into A, remainder IO | ||
| and | and | And A with Y | |
| xor | eor | Xor A with Y | |
| ior | ora | Or A with Y | |
| cma | Complement |
| Jump Instructions | 6502 | Description | Notes |
|---|---|---|---|
| jmp | jmp | ||
| jsp | jsr | Jump and Save PC | Program counter stored in accumulator |
| jda | Jump and Deposit | Jumps to Y+1 and puts a in Y as a parameter | |
| xct | Execute | Execute instruction outside program flow |
| Branch Instructions | 6502 | Description | Notes |
|---|---|---|---|
| idx | inc | Increment Y | |
| isp | inc, beq | Increment Y skip if now positive | Loops are done by using negative numbers! |
| sad | cmp, bne | Skip if A & Y different | Skips next instruction if not equal |
| sas | cmp, beq | Skip if A & Y equal | Skips next instruction if equal |
| sza | beq | Skip if A zero | |
| spa | bpl | Skip if plus | |
| sma | bmi | Skip if minus | |
| szo | bcc | Skip on zero overflow | |
| spi | cmp IO, bpl | Skip on IO positive | |
| szs | cmp SW, beq | Skip if switch is zero | |
| szf | Skip on zero program flag | Addresses 0001 to 0007 |
| Shift Operations | 6502 | Description | Notes |
|---|---|---|---|
| rar | ror | Rotate A right | |
| ral | rol | Rotate A left | |
| sar | asr | Shift A right | |
| sal | asl | Shift A left | |
| rir | Rotate IO right | ||
| ril | Rotate IO left | ||
| sir | Shift IO right | ||
| sil | Shift IO left | ||
| rcr | Rotate both right | ||
| rcl | Rotate both left | ||
| scr | Shift both right | ||
| scl | Shift rotate left |