🚀 go-pugleaf

In article <15341@auspex-gw.auspex.com>, guy@Auspex.COM (Guy Harris) writes:
|> 
|> In addition, AAM is claimed to take 17 cycles in the table on page E-5,
|> and an unsigned divide is claimed to take - surprise, surprise - 14 to
|> 17 cycles with a one-byte operand.
|> 
|> Sounds as if AAM was - at least in the implementations on which you
|> tried it - really the "divide AL by a one-byte immediate operand,
|> stuffing the quotient into AH and remainder in AL" instruction....
|> 
|> 10 hex is 16 decimal, and if D4 10 does a base-16 AAM, then it would be
|> 
|> 	AH = AL >> 4
|> 	AL = AL & 0xF
|> 
|> Try it with hex 11, and see if it does
|> 
|> 	AH = AL / 17
|> 	AL = AL MOD 17
|> 
|> Note, though, that they may have cut corners in future implementations,
|> such as the 586^H^H^HPentium, so that hex A is the only operand that
|> works correctly.
|> 
|> The same, of course, may well apply to *other* undocumented
|> instructions; programmer, beware!  (What's Latin for "programmer"? :-))
|> I've heard a claim that the bit-field instructions didn't completely
|> work, even on the 386; I've no idea whether there's any truth to that
|> claim or not.
|>
This instruction must be supported in future development. Reason is that Borland
uses this trick in it libraries. If this instruction is not supported, many program
do not run. I think I'm right.

Frank

examples: printf, scanf ...