Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

   ◄Summary►  ◄Timings►  ◄Example►
────────────────┬──────────────────────┬───────────────────────────────────
 FMUL [reg,reg] │ fmul   st,st(2)      │  87   130-145 (90-105) *
                │ fmul   st(5),st      │ 287   130-145 (90-105) *
                │ fmul                 │ 387   t=46-54 (49),f=29-57 (52) **
────────────────┼──────────────────────┼───────────────────────────────────
 FMULP reg,ST   │ fmulp st(6),st       │  87   134-148 (94-108) *
                │                      │ 287   134-148 (94-108) *
                │                      │ 387   29-57 (52) **
────────────────┼──────────────────────┼───────────────────────────────────
 FMUL memreal   │ fmul DWORD PTR [bx]  │  87   (s=110-125,l=154-168)+EA ***
                │ fmul shortreal[di+3] │ 287   s=110-125,l=154-168 ***
                │ fmul longreal        │ 387   s=27-35,l=32-57
────────────────┼──────────────────────┼───────────────────────────────────
 FIMUL memint   │ fimul int16          │  87   (w=124-138,d=130-144)+EA
                │ fimul warray[di]     │ 287   w=124-138,d=130-144
                │ fimul double         │ 387   w=76-87,d=61-82
────────────────┴──────────────────────┴───────────────────────────────────
*   The clocks in parentheses show times for short values--those with 40
    trailing zeros in their fraction because they were loaded from
    a short-real memory operand.
 
**  The clocks in parentheses show typical speeds.
 
*** If the register operand is a short value--having 40 trailing zeros in
    its fraction because it was loaded from a short-real memory operand--
    then the timing is (112-126)+EA on the 8087 or 112-126 on the 80287.
                                    -♦-