• parabolis (27/27) Jul 31 2004 I have poured over several documents and am at a loose end. I
• h3r3tic (12/12) Jul 31 2004 I don't get it either. Even that doesn't work for the same reason:
• Walter (3/30) Jul 31 2004 Try running obj2asm over it and look at the result.
• Walter (3/30) Jul 31 2004 The div instruction is generating the exception. Perhaps it's overflowin...
• parabolis (3/4) Jul 31 2004 Yes you are correct. I am certain it is the div instruction. I
• parabolis (9/11) Jul 31 2004 Thanks again. I did a search on idiv and found the following.
• Walter (4/7) Jul 31 2004 You can download the Intel instruction set manuals in PDF from Intel's w...

parabolis <parabolis softhome.net> writes:

I have poured over several documents and am at a loose end. I 
need help with making div and idiv work the way I expect them 
to. I keep getting a Win32 error when I try to use the following 
code:

================================================================
     typedef uint up4;

     up4 up4_div( up4 lhs, up4 rhs ) {
             up4 res;
             assert( rhs != 0 );
	    asm {
                 xor EAX, EAX;  // dividend bottom 32-bits to 0
                 mov EDX, lhs;  // dividend top 32-bits to lhs
                 div rhs;       // divide by rhs
                 mov res, EAX;  // return quotient
         }
         return res;
     }

     void main(char[][] args ) {
	up4 a = cast(up4)0xA0000001;
	up4 b = cast(up4)0xC0000000;
         up4_div( b, a );
     }

Output:
Error: Win32 Error
================================================================

I am expecting a result of ((lhs / rhs) * 2^32). Am I missing 
something simple?

h3r3tic <h3r3tic dev.null> writes:

I don't get it either. Even that doesn't work for the same reason:

up4 up4_div( up4 lhs, up4 rhs )
{
	asm {
		pusha;
		mov AX, 1;
		div AX;
		popa;
	}
	
	return 0;
}

"Walter" <newshound digitalmars.com> writes:

Try running obj2asm over it and look at the result.

"parabolis" <parabolis softhome.net> wrote in message
news:ceghrm$15de$1 digitaldaemon.com...
 I have poured over several documents and am at a loose end. I
 need help with making div and idiv work the way I expect them
 to. I keep getting a Win32 error when I try to use the following
 code:

 ================================================================
      typedef uint up4;

      up4 up4_div( up4 lhs, up4 rhs ) {
              up4 res;
              assert( rhs != 0 );
     asm {
                  xor EAX, EAX;  // dividend bottom 32-bits to 0
                  mov EDX, lhs;  // dividend top 32-bits to lhs
                  div rhs;       // divide by rhs
                  mov res, EAX;  // return quotient
          }
          return res;
      }

      void main(char[][] args ) {
 up4 a = cast(up4)0xA0000001;
 up4 b = cast(up4)0xC0000000;
          up4_div( b, a );
      }

 Output:
 Error: Win32 Error
 ================================================================

 I am expecting a result of ((lhs / rhs) * 2^32). Am I missing
 something simple?

"Walter" <newshound digitalmars.com> writes:

The div instruction is generating the exception. Perhaps it's overflowing.

"parabolis" <parabolis softhome.net> wrote in message
news:ceghrm$15de$1 digitaldaemon.com...
 I have poured over several documents and am at a loose end. I
 need help with making div and idiv work the way I expect them
 to. I keep getting a Win32 error when I try to use the following
 code:

 ================================================================
      typedef uint up4;

      up4 up4_div( up4 lhs, up4 rhs ) {
              up4 res;
              assert( rhs != 0 );
     asm {
                  xor EAX, EAX;  // dividend bottom 32-bits to 0
                  mov EDX, lhs;  // dividend top 32-bits to lhs
                  div rhs;       // divide by rhs
                  mov res, EAX;  // return quotient
          }
          return res;
      }

      void main(char[][] args ) {
 up4 a = cast(up4)0xA0000001;
 up4 b = cast(up4)0xC0000000;
          up4_div( b, a );
      }

 Output:
 Error: Win32 Error
 ================================================================

 I am expecting a result of ((lhs / rhs) * 2^32). Am I missing
 something simple?

parabolis <parabolis softhome.net> writes:

Walter wrote:
 The div instruction is generating the exception. Perhaps it's overflowing.

Yes you are correct. I am certain it is the div instruction. I 
had not idea an overflow would cause an exception however...

parabolis <parabolis softhome.net> writes:

Walter wrote:
 The div instruction is generating the exception. Perhaps it's overflowing.
 

Thanks again. I did a search on idiv and found the following.

http://www.jorgon.freeserve.co.uk/TestbugHelp/UseofIDIV.htm

If the result of the divide is larger than the data size of the 
destination again the processor will halt (in Windows an 
exception code 0C0000095h occurs).

If you have any links to well done ducmentation for x86 assembly 
then I could use them. The only substantial documentation I have 
is the "Intel 80386 Programmer's Reference 1986."

"Walter" <newshound digitalmars.com> writes:

"parabolis" <parabolis softhome.net> wrote in message
news:cegnpm$17rd$1 digitaldaemon.com...
 If you have any links to well done ducmentation for x86 assembly
 then I could use them. The only substantial documentation I have
 is the "Intel 80386 Programmer's Reference 1986."

You can download the Intel instruction set manuals in PDF from Intel's web
site. That's what I use.