⟦327013da7⟧

E3 Source Code



with Io_Exceptions;
use Io_Exceptions;
with Machine_Types;
use Machine_Types;
with System;

with Unchecked_Conversion;

package body Local_Io_Conf is

    -- Example implementation of local terminal I/O, stub version.
    -- The serial I/O code from the TDM configuration can be used
    -- to build an implementation of local_io that communicates with
    -- a terminal over an RS-232 connection.

    package Serial_Support is

        -- Borrowed from TDM configuration code.  NOTE -- if TDM is being
        -- used, no implementation of local_io may be used that would attempt
        -- to do I/O over the same serial port on the target that TDM uses.

        procedure Init;
        -- Does target hardware specific initializations including
        -- programming the serial I/O ports.

        procedure Put (B : Byte);
        -- Loops until the output port is ready. Then, puts the byte
        -- to the serial output device.

        procedure Get (B : out Byte; Got_Byte : out Boolean);
        -- Gets a byte if one is available from the serial input device.
        --
        -- NOTE: doesn't loop. Tests if input is available. If available,
        -- reads input byte and returns TRUE. Otherwise, returns FALSE
        -- immediately.  The routine below that uses this procedure just
        -- tests 'got_byte' in a tight loop, so a version that waits for
        -- a character would work as well.  The present procedure
        -- specification is used for compatibility with the TDM
        -- configuration code.

    end Serial_Support;

    package body Serial_Support is

        procedure Init is
            -- Does target hardware specific initializations including programming
            -- the serial I/O ports.
        begin
            null;
        end Init;

        procedure Put (B : Byte) is
            -- Loops until the output port is ready. Then, puts the byte to the
            -- serial output device.
        begin
            null;
        end Put;


        procedure Get (B : out Byte; Got_Byte : out Boolean) is
            -- Gets a byte if one is avaiable from the serial input device.
            --
            -- NOTE: doesn't loop. Tests if input is available. If available,
            -- reads input byte and returns TRUE. Otherwise, returns FALSE
            -- immediately.
        begin
            null;
        end Get;

    end Serial_Support;


    procedure Initialize (Device : Local_Device_Handle) is
    begin
        if Device = Dev0 then
            Serial_Support.Init;
        else
            raise Use_Error;
        end if;
    end Initialize;


    procedure Shutdown (Device : Local_Device_Handle) is
    begin
        null;
    end Shutdown;


    procedure Write_Char (Char : Machine_Types.Byte) is
        -- Write a single character, mapping line-feeds
    begin
        Serial_Support.Put (Char);
        if Char = Machine_Types.Byte (Character'Pos (Ascii.Lf)) then
            Serial_Support.Put (Character'Pos (Ascii.Cr));
        end if;
    end Write_Char;


    procedure Read (Device : Local_Device_Handle;
                    Addr : System.Address;
                    Count : in out Natural) is
        -- any special character processing (e.g. backspace)
        -- could be done here...this version just reads the next
        -- character, changing CR into LF

        C, Char : Machine_Types.Byte;
        for Char use at Addr;

        Got_Char : Boolean := False;
    begin
        if Device = Dev0 then
            if Count > 0 then
                while not Got_Char loop
                    Serial_Support.Get (C, Got_Char);
                end loop;
                -- change CR into LF
                if C = Byte (Character'Pos (Ascii.Cr)) then
                    C := Byte (Character'Pos (Ascii.Lf));
                end if;
                -- echo the character
                Write_Char (C);
                Char := C;
                Count := 1;
            else
                Count := 0;
            end if;
        else
            raise Use_Error;
        end if;
    end Read;


    procedure Write (Device : Local_Device_Handle;
                     Addr : System.Address;
                     Count : in out Natural) is
        use Machine_Types;

        Buf : array (1 .. Count) of Machine_Types.Byte;
        for Buf use at Addr;
    begin
        if Device = Dev0 then
            for I in Buf'Range loop
                Write_Char (Buf (I));
            end loop;
        else
            raise Use_Error;
        end if;
    end Write;


end Local_Io_Conf;
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⟦327013da7⟧ Ada Source

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