/ Resources / References / P-Code / P-Codes Defined
/ Resources / References / P-Code / P-Codes Defined |
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The second byte of the P-code instruction contains either 0 or a lexical level offset, or a condition code for the conditional jump instruction.
The last two bytes taken as a 16-bit integer form an operand which is a literal value, or a variable offset from a base in the stack, or a P-code instruction location, or an operation number, or a special routine number, depending on the op-code.
| P-Code | Hex OP-Code | Description |
|---|---|---|
| LIT 0,N | 0x00 | load literal value onto stack by incrementing stack pointer, writing N to data stack. |
| OPR 0,N | 0x01 | arithmetic or logical operation on top of stack |
| LOD L,N | 0x02 | load value of variable at level offset L, base offset N in stack onto top of stack |
| STO L,N | 0x03 | store value on top of stack into variable location at level offset L, base offset N in stack |
| CRL L,N | 0x04 | call PROC or FUNC at P-code location N declared at level offset L |
| INT 0,N | 0x05 | increment stackpointer (T) by N (may be negative) |
| JMP 0,N | 0x06 | jump to P-code location N |
| JPC C,N | 0x07 | jump if C=value on top of stack to P-code location N (C can = 0 or 1) |
| CSP 0,N | 0x08 | call standard procedure number N |
| LODX L,N | 0x12 | load indexed (array) variables as above |
| STOX L,N | 0x13 | store indexed variable as above |
| LIT 0,NN | literal: push NN |
| OPR 0,0 | process and function, return operation |
| OPR 0,1 | negate: POP A, PUSH (-A) |
| OPR 0,2 | add: POP A, POP B, PUSH (B+A) |
| OPR 0,3 | subtract: POP A, POP B, PUSH (B-A) |
| OPR 0,4 | multiply: POP A, POP B, PUSH (B*A) |
| OPR 0,5 | divide: POP A, POP B, PUSH (B/A) |
| OPR 0,6 | low bit: POP A, PUSH (A and 1) |
| OPR 0,7 | mod: POP A, POP B, PUSH (B mod A) |
| OPR 0,8 | test equal: POP A, POP B, PUSH (B=A) |
| OPR 0,9 | test not equal: POP A, POP B, PUSH (B<>A) |
| OPR 0,10 | test less than: POP A, POP B, PUSH (B<A) |
| OPR 0,11 | test greater than or equal to: POP A, POP B, PUSH (B>=A) |
| OPR 0,12 | test greater than: POP A, POP B, PUSH (B>A) |
| OPR 0,13 | test less than or equal to: POP A, POP B, PUSH (B<=A) |
| OPR 0,14 | logical OR: POP A, POP B, PUSH (B or A) |
| OPR 0,15 | logical AND: POP A, POP B, PUSH (B and A) |
| OPR 0,16 | logical XOR: POP A, PUSH (xor A) |
| OPR 0,17 | logical NOT: POP A, PUSH (not A) |
| OPR 0,18 | shift left: POP A, POP B, PUSH (B left shifted A bits) |
| OPR 0,19 | shift right: POP A, POP B, PUSH (B right shifted A bits) |
| OPR 0,20 | increment: POP A, PUSH A+1 |
| OPR 0,21 | decrement: POP A, PUSH A-1 |
| OPR 0,22 | copy: POP A, PUSH A, PUSH A |
| OPR 0,23 | random number: PUSH generated number |
| LOD L,D | load a word: LOAD A from (base of level offset L)+D, PUSH A |
| LOD 255,0 | load byte from memory address which is on top of stack onto top of stack: POP address, load A with byte from address, PUSH A |
| LODX L,D | load a word by index: POP index, load A from (base of level offset)+D+index, PUSH A |
| STO L,D | store a word: POP A, store A at (base of level offset L)+D |
| **STO 255,0 | store a byte: POP A, POP address, store low byte at address |
| STOX L,D | store a word by index: POP index, POP A, store A at (base of level offset L)+D+index |
| CAL L,A | call procedure or function at p-code location A, with base at level offset L |
| **CAL 255,0 | call procedure address in memory: POP address, PUSH return address, JUMP to address |
| INT 0,NN | add NN to stack pointer |
| JMP 0,A | jump to P-code location A |
| JPC 0,A | jump if true : POP A, IF (A AND 1) = 0 then jump to location A |
| **JPC 1,A | jump if true : POP A, IF (A AND 1) = 1 then jump to location A? |
| CSP 0,0 | input 1 character: INPUT A, PUSH A |
| CSP 0,1 | output 1 character: POP A, OUTPUT A |
| CSP 0,2 | input an integer: INPUT A#, PUSH A |
| CSP 0,3 | output an integer: POP A, OUTPUT A# |
| **CSP 0,4 | input a hexadecimal number |
| **CSP 0,5 | output a hexadecimal number |
| CSP 0,8 | output a character string: POP A, FOR I := 1 to A DO BEGIN POP B, OUTPUT B, END |
| *CSP 0,9 | semaphore close: details to come |
| *CSP 0,10 | semaphore create: details to come |
| *CSP 0,11 | semaphore open: details to come |
| *CSP 0,12 | semaphore signal: details to come |
| *CSP 0,13 | semaphore wait: details to come |
| *CSP 0,14 | shared memory close: details to come |
| *CSP 0,15 | shared memory create: details to come |
| *CSP 0,16 | shared memory open: details to come |
| *CSP 0,17 | shared memory read: details to come |
| *CSP 0,18 | shared memory write: details to come |
| *CSP 0,19 | shared memory size: details to come |
| *CSP 0,20 | file allocate: details to come |
| *CSP 0,21 | file open: details to come |
| *CSP 0,22 | file create: details to come |
| *CSP 0,23 | file close: details to come |
| *CSP 0,24 | file end of file (EOF): details to come |
| *CSP 0,25 | file delete: details to come |
| *CSP 0,26 | file read: details to come |
| *CSP 0,27 | file write: details to come |
NOTE: When a logical operation is performed a TRUE result
is indicated by a 1 and a 0 inidicates FALSE.