BDC - Binary Coded Decimal

[Bert Mariani]

Hello Mahmoud, Youssef et ALL

Intel Chips have BCD Binary Coded Decimal instructions in 32 Bit Mode.

Using 64 Bit mode the BCD instructions do not exist  ( Bad Intel) !!

Note: Banking does all their financial math using BCD on mainframes with Cobol.

Because floating point causes rounding errors. BCD is 100% accurate.

Attached:  bcd_add_msvc.c 

                   bcd_add.ring

The C-code runs even though my machine is 64 Bit

It uses the C to ASM instructions to operate ( see code)

It is currently coded to use upt o 40 BCD digits - a huge number.

I can run the bcd_add_msvc.exe on my 64 bit HP-I5

See below

I want to Use Ring and CFFI to run the  bcd_add_msvc.c   program.

Issues:  Ring-64 uses only DLL-64

               CFFI is installed under C:\Ring   ( 64)

               It needs to run in Ring-32

I downloaded a 2nd  --  C:\Ring-32\Ring 

I managed to install CFFI in C:\Ring-32\Ring

But run into problems. See errors below.

Is there a way to solve this mess ?

======================

32 BIT RING
cd Ring32\ring
-----
c:\Ring32\ring> C:\Ring32\ring\bin\ringpm.exe install ring-cffi from ysdragon
     Installing ring-cffi (master) ---> ring-cffi (1.0.0)
     Download Package Files For ring-cffi
      ------

c:\Ring32\ring>cd  c:\MyStuff\AA-BCD    // <<<===
c:\MyStuff\AA-BCD>C:\ring32\ring\bin\ring.exe BCD-Add.ring  // <<<===

Error (E9) : Can't open file cffi.ring
BCD-Add.ring Line (38) Error (C27) : Syntax Error!
BCD-Add.ring errors count : 1

c:\MyStuff\AA-BCD>

==========================

Working C

How to Compile and Run bcd_add_msvc.c 

Open "Developer Command Prompt for VS" from the Start menu
     **********************************************************************
     ** Visual Studio 2026 Developer Command Prompt v18.7.3
     ** Copyright (c) 2026 Microsoft Corporation
     **********************************************************************
C:\Program Files\Microsoft Visual Studio\18\Community>

cd c:\MyStuff\AA-BCD

c:\MyStuff\AA-BCD>cl /TC bcd_add_msvc.c
     Microsoft (R) C/C++ Optimizing Compiler Version 19.51.36248 for x86
     Copyright (C) Microsoft Corporation.  All rights reserved.   
     bcd_add_msvc.c
     Microsoft (R) Incremental Linker Version 14.51.36248.0
     Copyright (C) Microsoft Corporation.  All rights reserved.   
     /out:bcd_add_msvc.exe
     bcd_add_msvc.obj

   //=========================
   // RUN
c:\MyStuff\AA-BCD>bcd_add_msvc.exe
Enter first number (up to 38 integer digits, 2 decimal places, e.g. 123.45): 123123123123123.98
Enter second number (up to 38 integer digits, 2 decimal places, e.g. 123.45): 345345345345345.07

Input 1 ->  BCD: 123123123123123.98
Input 2 ->  BCD: 345345345345345.07
Sum     ->  BCD: 468468468468469.05

c:\MyStuff\AA-BCD>

================================

 

Thanks

Bert Mariani

[Mahmoud Fayed]

Hello Bert

Thanks for sharing the code :D

Keep up the GREAT WORK :D

Greetings,

Mahmoud