Author Topic: Possible problem in NASM opcode table?  (Read 12519 times)


  • Guest
Possible problem in NASM opcode table?
« on: February 22, 2008, 11:07:31 AM »
Like the title says. From the opcode table:

Jcc      imm|near      \322\1\x0F\330\x80\64      386
Jcc      imm16|near      \320\1\x0F\330\x80\64      386
Jcc      imm32|near      \321\1\x0F\330\x80\64      386
Jcc      imm|short      \330\x70\50         8086,ND
Jcc      imm         \370\330\x70\50         8086,ND
Jcc      imm         \1\x0F\330\x80\64      386,ND
Jcc      imm         \330\x71\373\1\xE9\64      8086,ND
Jcc      imm         \330\x70\50         8086

Specifically, the section \330\x71\373\1\xE9\64. Doesn't seem to make any sense, can't find it in the intel manual. Is it a bug?

.......Also, mov rax, cr0 assembles without an error in 32bit mode


  • Guest
Re: Possible problem in NASM opcode table?
« Reply #1 on: March 12, 2008, 08:23:57 PM »
Note the "8086". Also note the "E9", which is the opcode for a near jmp.

I expect that line describes the encoding of near conditional jumps for 8086.