# The OS/K Team licenses this file to you under the MIT license.
# See the LICENSE file in the project root for more information.

#---------------------------------------------------------------------------#
# Jump instructions                                                         #
#---------------------------------------------------------------------------#

#
# Jump (JMP) instruction
#
#       RIP = $1
#
jmp ri

#
# RCX-dependent jump (LOOP) instruction
#
#       IF (RCX > 0) THEN
#           RCX = RCX - 1
#           RIP = $1
#       FI  
#
loop ri

#
# Conditional absolute jumps (B)
#
#       COMPARE($1, $2)
#
#       IF (COND) THEN
#           RIP = $3
#       FI
#
# Sets CF, OF, ZF and SF according to the comparison's results
#
# This instruction is special in that the COND field specified is not evaluated
# before the instruction is executed, but after the comparison it effectuates
#
# Suffixing B with the REP suffix results in undefined behavior
#
b rm ri ri


#---------------------------------------------------------------------------#
# Stack manipulation instructions                                           #
#---------------------------------------------------------------------------#

#
# Unconditional jump with possible return (CALL)
#
#       PUSH(RIP)
#       JMP(RIP)
#
call ri
call i ri
call i ri ri

#
# Return to caller (RET)
#
#       POP(RIP)
#
ret

#
# Make new stack frame (ENTER)
#
#       PUSH(RBP)
#       RBP = RSP
#       RSP = RSP - $1
#
enter i

#
# Leave stack frame (LEAVE)
#
#       RSP = RBP
#       POP(RBP)
#
leave

#
# PUSH value onto stack
#
#       RSP = RSP - 8
#       *RSP = $1
#
push rim

#
# POP value from stack
#
#       $1 = *RSP
#       RSP = RSP + 8
#
pop r

#---------------------------------------------------------------------------#
# Movement instructions                                                     #
#---------------------------------------------------------------------------#

#
# Load Effective Address (LEA) instruction
#
#       $1 = ADDR($2)
#
# For instance:
#       LEA RAX, [RBX + RCX * 2 + 4]
# will result in:
#       RAX = RBX + RCX * 2 + 4
#
# Preserves all flags
#
lea r m

#
# Movement with sign-extension (MOV) instruction
#
#       $1 = $2
#
mov r rim
mov m ri

#
# Movement with sign-extension (MOVSXx) instruction
#
#       $1 = SignExtend($2 & (2^(8 * sizeof(x)) - 1)
#
movsxb r r
movsxw r r
movsxl r r

#
# Movement with zero-extension (MOVZX) instruction
#
#       $1 = ZeroExtend($2)
#
movzx r m

#
# Exchange (XCHG) instruction
#
#       $_ = $1
#       $1 = $2
#       $2 = $_
#
xchg r rm