[fpc-devel] EBCDIC (was On a port of Free Pascal to the IBM 370)

[michael.vancanneyt at wisa.be]

On Mon, 30 Jan 2012, rvmartin2 at ntlworld.com wrote:

> michael.vancanneyt at wisa.be wrote the following on 30/01/12 14:49:53:
>
>> I think the reason for producing an ASCII version first is very simple:
>> All FPC sources - including the compiler - are in ASCII encoding.
>
> I don't understand this statement - ASCII and EBCDIC are just human representations of a computer's internal code.
> I write my programs in the Latin (or Roman) alphabet and the computer does the rest.
> When I was writing VS/Pascal programs I used the same source code as input to VS/Pascal on the mainframe and to Virtual Pascal on the PC.
>
> Unless the FP source code is to be fed into a mainframe compiler like
> IBM's VS/Pascal or the Stanford compiler then the first step is surely to
> write a backend for the (eg PC) compiler to produce 370 assembler code. 
> Producing EBCDIC rather than ASCII sounds a trivial part of the task.

I had in mind the following scenario:

1) Somehow we build - using cross-compilation - a first version of the
   compiler that actually runs on the 370. This binary is transferred to a
   370 machine.

2) The sources of the compiler and RTL are transferred to the 370.
    I assume that after the file transfer, the sources are still in ASCII format ?

3) At that point the compiler can try to recompile itself on the 370
    machine.

Unless you have performed some tranformation of the compiler/RTL sources, 
the compiler in step 3 will read and compile from ASCII sources, no ?

Michael.