Sam Stevens
7bd26502ff
Re-formatted as markdown. Changed how flags are accessed. Started flag documentation. Added syscalls.
95 lines
2.9 KiB
Markdown
95 lines
2.9 KiB
Markdown
## Features
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* 4 16-bit Registers
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* 254 8-bit Flag Registers
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* Start at end of memory from 0xFF00
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* See [FLAGS.md](FLAGS.md)
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* 255 8-bit Ports
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* 0x00 console in/out
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* 0x01 tape in/out
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* 0x02-0x20 Reserved
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* Others Implementation Specific
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* 255 Syscall routines
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* Program Counter
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* Call Stack 16 x 16-bit
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* 64K x 8-bit Memory
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* MSB / big-endian
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## ASM Parameters
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| Type | Symbol | Example/Use |
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| ----------------- | ------ | ----------------- |
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| Registers | R | A-D |
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| Marker | : | :XYZ |
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| Absolute Location | # | 0-65535 \| 0xFFFF |
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## Location Parameter (@)
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| Code | ASM | Type | Values |
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| ---- | --- | ------------------- | -------------------------------- |
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| 0x0 | P | Port | 0-255 \| 0xFF |
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| 0x1 | R | Register | A-D |
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| 0x2 | M | Memory | 0-65535 \| 0xFFFF |
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| 0x3 | L | Immediate | 0-65535 \| 0xFFFF \| 'a' \| "a" |
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| 0x4 | A | Address In Register | A-D |
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## ASM Instructions
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| Hex | ASM | Parameters | Notes |
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| ---- | ----- | ---------------- | ----- |
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| **Misc**
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| 0x00 | NOP | |
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| **Load/Save**
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| 0x10 | LOAD | [R] [@] |
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| 0x11 | SAVE | [R] [@] |
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| 0x12 | LOADH | [R] [@] |
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| 0x13 | LOADL | [R] [@] |
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| 0x14 | SAVEH | [R] [@] |
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| 0x15 | SAVEL | [R] [@] |
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| **Math**
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| 0x20 | CLR | [R] |
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| 0x21 | ADD | [R] [@] |
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| 0x22 | SUB | [R] [@] |
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| 0x23 | DIV | [R] [@] |
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| 0x24 | MUL | [R] [@] |
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| 0x25 | INC | [R] |
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| 0x26 | DEC | [R] |
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| **Logic**
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| 0x30 | NOT | [R] |
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| 0x31 | AND | [R] [@] |
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| 0x32 | OR | [R] [@] |
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| 0x33 | XOR | [R] [@] |
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| 0x34 | SHL | [R] [0-7] | Shift Left
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| 0x35 | SHR | [R] [0-7] | Shift Right
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| 0x36 | BTS | [R] [0-7] | Bit Set
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| 0x37 | BTC | [R] [0-7] | Bit Clear
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| **Stack**
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| 0x40 | CALL | [#\|:] |
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| 0x41 | RET | |
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| **Program Flow**
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| 0x50 | HALT | |
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| 0x51 | JMP | [#\|:] |
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| 0x52 | JZ | [R] [#\|:] |
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| 0x53 | JNZ | [R] [#\|:] |
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| 0x54 | JBS | [R] [0-7] [#\|:] |
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| 0x55 | JBC | [R] [0-7] [#\|:] |
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| **System**
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| 0x60 | SYS | [0-255] | Syscall, parameters depend on call
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### Assembler Only
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| ASM | Parameters | Notes |
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| ------ | ---------- | ------------ |
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| ORIGIN | [#] | Sets the Memory Address for the next instruction |
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## Program Format
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ORIGIN 0
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:MARKERA JMP :MARKERB # This is a comment
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:MARKERB INC A
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JMP :MARKERA
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[...ASM Instrictions...]
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MEMORY
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0x100 "string abcd"
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100 0x00 00 00
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