Thunder instruction set

Note: this needs updating with new spellings like LDCu, new opcodes like BNGEf, and to remove the RET instruction.

ADD   reg, reg, imm	Integer arithmetic
ADD   reg, reg, reg 
SUB   reg, reg, imm 
SUB   reg, reg, reg 
MUL   reg, reg, imm
MUL   reg, reg, reg 

AND   reg, reg, imm 	Bitwise logical operations
AND   reg, reg, reg 
OR    reg, reg, imm 
OR    reg, reg, reg 
XOR   reg, reg, imm 
XOR   reg, reg, reg 

NEG   reg, reg		Integer unary minus
NOT   reg, reg    	Bitwise negation
SXT   reg, reg 		Sign extend 16 bits to 32

LSH   reg, reg, imm 	Logical shift left
LSH   reg, reg, reg 
RSH   reg, reg, imm 	Arithmetic shift right
RSH   reg, reg, reg 
RSHU  reg, reg, imm 	Logical shift right
RSHU  reg, reg, reg 
ROR   reg, reg, imm	Rotate right
ROR   reg, reg, reg

BEQ   reg, imm, lab 	Integer conditional branches
BEQ   reg, reg, lab 
BGEQ  reg, imm, lab 
BGEQ  reg, reg, lab 
BGT   reg, imm, lab 
BGT   reg, reg, lab 
BLEQ  reg, imm, lab 
BLEQ  reg, reg, lab 
BLT   reg, imm, lab 
BLT   reg, reg, lab 
BNEQ  reg, imm, lab 
BNEQ  reg, reg, lab 

BGEQU reg, imm, lab 	Unsigned conditional branches
BGEQU reg, reg, lab
BGTU  reg, imm, lab
BGTU  reg, reg, lab
BLEQU reg, imm, lab
BLEQU reg, reg, lab
BLTU  reg, imm, lab 
BLTU  reg, reg, lab 

JUMP  lab		Unconditional jump
JUMP  reg 

EQ    reg, reg, imm	Integer comparisons with boolean result
EQ    reg, reg, reg 
GEQ   reg, reg, imm
GEQ   reg, reg, reg
GT    reg, reg, imm 
GT    reg, reg, reg 
LEQ   reg, reg, imm
LEQ   reg, reg, reg
LT    reg, reg, imm 
LT    reg, reg, reg 
NEQ   reg, reg, imm
NEQ   reg, reg, reg

PREP  imm		Prepare procedure call

CALL  imm		Perform procedure call
CALL  reg

ARG   imm		Save outgoing argument
ARG   reg

RET			Return (removed in recent versions)

GETARG reg, imm		Fetch incoming argument

MOV   reg, imm		Move to register
MOV   reg, lab
MOV   reg, reg

LDC   reg, imm		Load character with sign extension
LDC   reg, reg
LDC   reg, reg, imm

LDCU  reg, imm		Load character with zero extension
LDCU  reg, reg
LDCU  reg, reg, imm

LDKW  reg, imm		Undocumented

LDS   reg, imm		Load short with sign extension
LDS   reg, reg
LDS   reg, reg, imm

LDSU  reg, imm		Load short with zero extension
LDSU  reg, reg
LDSU  reg, reg, imm

LDW   reg, imm		Load word
LDW   reg, reg
LDW   reg, reg, imm

STC   reg, imm		Store character
STC   reg, reg
STC   reg, reg, imm

STS   reg, imm		Store short
STS   reg, reg
STS   reg, reg, imm

STW   reg, imm		Store word
STW   reg, reg
STW   reg, reg, imm


*** Floating Point

ADDF  freg, freg, freg	Floating point arithmetic
ADDD  freg, freg, freg
SUBF  freg, freg, freg
SUBD  freg, freg, freg
MULF  freg, freg, freg
MULD  freg, freg, freg
DIVF  freg, freg, freg
DIVD  freg, freg, freg

NEGF  freg, freg	Floating point negation
NEGD  freg, freg

ZEROF freg		Load zero into floating point register
ZEROD freg

BEQF  freg, freg, lab	Floating point conditional branches
BEQD  freg, freg, lab
BGEQF freg, freg, lab
BGEQD freg, freg, lab
BGTF  freg, freg, lab
BGTD  freg, freg, lab
BLEQF freg, freg, lab
BLEQD freg, freg, lab
BLTF  freg, freg, lab
BLTD  freg, freg, lab
BNEQF freg, freg, lab
BNEQD freg, freg, lab

EQF reg, freg, freg	Floating point comparisons with boolean result
EQD reg, freg, freg
GEQF reg, freg, freg
GEQD reg, freg, freg
GTF reg, freg, freg
GTD reg, freg, freg
LEQF reg, freg, freg
LEQD reg, freg, freg
LTF reg, freg, freg
LTD reg, freg, freg
NEQF freg, freg, freg
NEQD freg, freg, freg

CONVDF freg, freg	Convert double to float
CONVFD freg, freg	Convert float to double
CONVIF freg, reg	Convert integer to float
CONVID freg, reg	Convert integer to double
CONVFI reg, freg	Convert float to integer
CONVDI reg, freg	Convert double to integer       

LDKW freg, imm		Undocumented

LDW freg, imm		Floating point load
LDW freg, reg
LDW freg, reg, imm

LDQ freg, imm		Double precision load
LDQ freg, reg
LDQ freg, reg, imm

STW freg, imm		Floating point store
STW freg, reg
STW freg, reg, imm

STQ freg, imm		Double precision store
STQ freg, reg
STQ freg, reg, imm

MOV freg, freg		Move between registers
MOV freg, reg
MOV reg, freg