[comp.sys.ibm.pc] What is this opcode?

bill@twwells.uucp (T. William Wells) (03/29/89)

While mousing around in my unix kernel, I noticed an instruction
whose first two bytes are D0 F1. The disassembler doesn't know about
it, adb doesn't know about it, and my 386 book doesn't know about it.

Do you?

Please respond via e-mail; I will summarize and post.

---
Bill                            { uunet | novavax } !twwells!bill
(BTW, I'm may be looking for a new job sometime in the next few
months.  If you know of a good one where I can be based in South
Florida do send me e-mail.)

bill@twwells.uucp (T. William Wells) (04/03/89)

Recently, I sent:

: While mousing around in my unix kernel, I noticed an instruction
: whose first two bytes are D0 F1. The disassembler doesn't know about
: it, adb doesn't know about it, and my 386 book doesn't know about it.
:
: Do you?
:
: Please respond via e-mail; I will summarize and post.

Here is the summary:

Several people pointed out that the opcode is in the shift group of
opcodes and would, logically, be an alternate encoding of SAL CL,1.
One says that his disassembler returns that instruction.  This is the
answer I believe, since it fits with how I might imagine a chip
designer would have done things. The people with this answer are:

	nbires.NBI.COM!maa (Mark Armbrust)
	cup.portal.com!Devin_E_Ben-Hur
	tekgvs.LABS.TEK.COM!toma (Tom Almy)
	shapetc!wilson (Tony Wilson)

Thanks all.

---
Bill                            { uunet | novavax } !twwells!bill
(BTW, I'm may be looking for a new job sometime in the next few
months.  If you know of a good one where I can be based in South
Florida do send me e-mail.)