Alan Ingleby wrote:
One other point to note is that the DB processor cannot multiply 32 bit integers. This is emulated transparently by the compiler, so it isn't immediately obvious. Watch out for 32 bit multiplies.
Actually, the 68000 CPU core cannot do any hardware multiplies; all multiplies are emulated. There are 68k 16x32 MULU and MULS instructions, but they emulated in microcode by double pumping the 16-bit adder, and thus takes 40 or 42 clock cycles to complete.
To be fair, the P4 doesn't have a single cycle integer multiplier either; instead it has more than one pipelined floating point multiply-accumulator, each capable of returning one multiply result per cycle. The 200 MHz DSP inside the OMAP inside the m550 *does* have a single cycle multiplier. Ron Nicholson HotPaw <http://www.hotpaw.com/rhn/hotpaw> -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
