PSASM

0.3.0-preview

functions/private/.inst.ps1

function .inst {
    [PSASM()] param (
        [Parameter(Mandatory=$true)]
        [Alias("mn")]
        # [ValidateScript({[MOS6502]::OpCodes.$_}, ErrorMessage="Unknown mnemonic: '{0}'")]
        [string]$Mnemonic,

        [Parameter(Mandatory=$true)]
        [Alias("am")]
        # [ValidateScript({[MOS6502]::OpCodes.$Mnemonic.$_}, ErrorMessage="Unknown addressing mode '{0}' for mnemonic")]
        [string]$AddressingMode,

        [Parameter(Mandatory=$false)]
        [Alias("op")]
        [object]$Operand,

        [string]$InvocationFile,
        [int]$InvocationLine
    )

    if (-not [MOS6502]::opcodes.$Mnemonic.ContainsKey($AddressingMode)) {
        throw "Unknown addressing mode '$AddressingMode' for mnemonic '$Mnemonic' at line $InvocationLine in file '$InvocationFile'."
    }

    if($Operand -lt 256) {
        switch ($AddressingMode) {
            'Absolute' {
                if ([MOS6502]::OpCodes.$Mnemonic.ZeroPage) {
                    $AddressingMode = "ZeroPage"
                }
            }
            'AbsoluteIndexedX' {
                if ([MOS6502]::OpCodes.$Mnemonic.ZeroPageIndexedX) {
                    $Addressingmode = 'ZeroPageIndexedX'
                }
            }
            'AbsoluteIndexedY' {
                if ([MOS6502]::OpCodes.$Mnemonic.ZeroPageIndexedY) {
                    $Addressingmode = 'ZeroPageIndexedY'
                }
            }
        }
    }

    if ($AddressingMode -match 'Relative') {
        $Operand = [byte](($Operand - $psasm.Segments.Current.PC - 2) -band 255)
    }

    if ([MOS6502]::OperandSize.$AddressingMode -eq 16) {
        $psasm.OpAdd([MOS6502]::OpCodes.$Mnemonic.$AddressingMode, ($Operand -band 0xffff), $InvocationFile, $InvocationLine)
    }
    if ([MOS6502]::OperandSize.$AddressingMode -eq 8) {
        $psasm.OpAdd([MOS6502]::OpCodes.$Mnemonic.$AddressingMode, [byte]($Operand -band 0xff), $InvocationFile, $InvocationLine)
    }
    if ([MOS6502]::OperandSize.$AddressingMode -eq 0) {
        $psasm.OpAdd([MOS6502]::OpCodes.$Mnemonic.$AddressingMode, $InvocationFile, $InvocationLine)
    }
}