From d23dba2cc2da970d69d89320107ef436e92ce8ed Mon Sep 17 00:00:00 2001 From: David Schmenk Date: Thu, 12 Jun 2014 23:01:34 -0700 Subject: [PATCH] Update Architecture.md --- doc/Architecture.md | 131 ++++++++++++++++++++++---------------------- 1 file changed, 66 insertions(+), 65 deletions(-) diff --git a/doc/Architecture.md b/doc/Architecture.md index 2f1183f..f44e73d 100644 --- a/doc/Architecture.md +++ b/doc/Architecture.md @@ -19,70 +19,71 @@ One of the biggest problems to overcome with the 6502 is its very small hardware ### The Bytecodes The compact code representation comes through the use of opcodes closely matched to the PLASMA compiler. They are: -| OPCODE | Description -|:------:|----------------------------------- -| ZERO | push zero on the stack -| ADD | add top two values, leave result on top -| SUB | subtract next from top from top, leave result on top -| MUL | multiply two topmost stack values, leave result on top -| DIV | divide next from top by top, leave result on top -| MOD | divide next from top by top, leave remainder on top -| INCR | increment top of stack -| DECR | decrement top of stack -| NEG | negate top of stack -| COMP | compliment top of stack -| AND | bit wise AND top two values, leave result on top -| IOR | bit wise inclusive OR top two values, leave result on top -| XOR | bit wise exclusive OR top two values, leave result on top -| LOR | logical OR top two values, leave result on top -| LAND | logical AND top two values, leave result on top -| SHL | shift left next from top by top, leave result on top -| SHR | shift right next from top by top, leave result on top -| IDXB | add top of stack to next from top, leave result on top (ADD) -| IDXW | add 2X top of stack to next from top, leave result on top -| NOT | logical NOT of top of stack -| LA | load address -| LLA | load local address from frame offset -| CB | constant byte -| CW | constant word -| SWAP | swap two topmost stack values -| DROP | drop top stack value -| DUP | duplicate top stack value -| PUSH | push top to call stack -| PULL | pull from call stack -| BRGT | branch next from top greater than top -| BRLT | branch next from top less than top -| BREQ | branch next from top equal to top -| BRNE | branch next from top not equal to top -| ISEQ | if next from top is equal to top, set top true -| ISNE | if next from top is not equal to top, set top true -| ISGT | if next from top is greater than top, set top true -| ISLT | if next from top is less than top, set top true -| ISGE | if next from top is greater than or equal to top, set top true -| ISLE | if next from top is less than or equal to top, set top true -| BRFLS | branch if top of stack is zero -| BRTRU | branch if top of stack is non-zero -| BRNCH | branch to address -| CALL | sub routine call with stack parameters -| ICAL | sub routine call to indirect address on stack top with stack parameters -| ENTER | allocate frame size and copy stack parameters to local frame -| LEAVE | deallocate frame and return from sub routine call -| RET | return from sub routine call -| LB | load byte from top of stack address -| LW | load word from top of stack address -| LLB | load byte from frame offset -| LLW | load word from frame offset -| LAB | load byte from absolute address -| LAW | load word from absolute address -| SB | store top of stack byte into next from top address -| SW | store top of stack word into next from top address -| SLB | store top of stack into local byte at frame offset -| SLW | store top of stack into local word at frame offset -| SAB | store top of stack into byte at absolute address -| SAW | store top of stack into word at absolute address -| DLB | duplicate top of stack into local byte at frame offset -| DLW | duplicate top of stack into local word at frame offset -| DAB | duplicate top of stack into byte at absolute address -| DAW | duplicate top of stack into word at absolute address +| OPCODE | Name | Description +|:------:|:------:|----------------------------------- +| $00 | ZERO | push zero on the stack +| $02 | ADD | add top two values, leave result on top +| $04 | SUB | subtract next from top from top, leave result on top +| $06 | MUL | multiply two topmost stack values, leave result on top +| $08 | DIV | divide next from top by top, leave result on top +| $0A | MOD | divide next from top by top, leave remainder on top +| $0C | INCR | increment top of stack +| $0E | DECR | decrement top of stack +| $10 | NEG | negate top of stack +| $12 | COMP | compliment top of stack +| $14 | AND | bit wise AND top two values, leave result on top +| $16 | IOR | bit wise inclusive OR top two values, leave result on top +| $18 | XOR | bit wise exclusive OR top two values, leave result on top +| $1A | SHL | shift left next from top by top, leave result on top +| $1C | SHR | shift right next from top by top, leave result on top +| $02 | IDXB | add top of stack to next from top, leave result on top (ADD) +| $1E | IDXW | add 2X top of stack to next from top, leave result on top +| $20 | NOT | logical NOT of top of stack +| $22 | LOR | logical OR top two values, leave result on top +| $24 | LAND | logical AND top two values, leave result on top +| $26 | LA | load address +| $28 | LLA | load local address from frame offset +| $2A | CB | constant byte +| $2C | CW | constant word +| $2E | SWAP | swap two topmost stack values +| $30 | DROP | drop top stack value +| $32 | DUP | duplicate top stack value +| $34 | PUSH | push top to call stack +| $36 | PULL | pull from call stack +| $38 | BRGT | branch next from top greater than top +| $3A | BRLT | branch next from top less than top +| $3C | BREQ | branch next from top equal to top +| $3E | BRNE | branch next from top not equal to top +| $40 | ISEQ | if next from top is equal to top, set top true +| $42 | ISNE | if next from top is not equal to top, set top true +| $44 | ISGT | if next from top is greater than top, set top true +| $46 | ISLT | if next from top is less than top, set top true +| $48 | ISGE | if next from top is greater than or equal to top, set top true +| $4A | ISLE | if next from top is less than or equal to top, set top true +| $4C | BRFLS | branch if top of stack is zero +| $4E | BRTRU | branch if top of stack is non-zero +| $50 | BRNCH | branch to address +| $52 | IBRNCH | branch to address on stack top +| $54 | CALL | sub routine call with stack parameters +| $56 | ICAL | sub routine call to address on stack top with stack parameters +| $58 | ENTER | allocate frame size and copy stack parameters to local frame +| $5A | LEAVE | deallocate frame and return from sub routine call +| $5C | RET | return from sub routine call +| $60 | LB | load byte from top of stack address +| $62 | LW | load word from top of stack address +| $64 | LLB | load byte from frame offset +| $66 | LLW | load word from frame offset +| $68 | LAB | load byte from absolute address +| $6A | LAW | load word from absolute address +| $6C | DLB | duplicate top of stack into local byte at frame offset +| $6E | DLW | duplicate top of stack into local word at frame offset +| $70 | SB | store top of stack byte into next from top address +| $72 | SW | store top of stack word into next from top address +| $74 | SLB | store top of stack into local byte at frame offset +| $76 | SLW | store top of stack into local word at frame offset +| $78 | SAB | store top of stack into byte at absolute address +| $7A | SAW | store top of stack into word at absolute address +| $7C | DAB | duplicate top of stack into byte at absolute address +| $7E | DAW | duplicate top of stack into word at absolute address The opcodes were developed over time by starting with a very basic set of operations and slowly adding opcodes when the PLASMA compiler could improve code density or performance.