x86prime instructions and encoding
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Encoding:                                   Assembler           Operation

00000000 00000000                           stop                stop the machine
00000001 0000ssss                           ret s               return from function call
0001aaaa ddddssss                           op s,d              reg/reg arithmetic (see below)
00100001 ddddssss                           movq s,d            reg->reg copy
00110001 ddddssss                           movq (s),d          load (memory -> reg copy)
00111001 ddddssss                           movq d,(s)          store (reg -> memory copy)
-
0100cccc ddddssss pp...32...pp              cb<c> s,d,p         compare and continue at p if... (see below)
01001110 dddd0000 pp...32...pp              call p,d            function call
01001111 00000000 pp...32...pp              jmp p               continue at p
0101aaaa dddd0000 ii...32...ii              op $i,d             constant/reg arithmethic(see below)
01100100 dddd0000 ii...32...ii              movq $i,d           constant -> register
01110101 ddddssss ii...32...ii              movq i(s),d         load (memory -> reg copy)
01111101 ddddssss ii...32...ii              movq d,i(s)         store (reg -> memory copy)
-
10000001 ddddssss                           leaq (s),d          s -> d
10010010 dddd0000 zzzzvvvv                  leaq (,z,v),d       z*v -> d
10010011 ddddssss zzzzvvvv                  leaq (s,z,v),d      s+z*v -> d
10100100 dddd0000 ii...32...ii              leaq i,d            i -> d
10100101 ddddssss ii...32...ii              leaq i(s),d         i+s -> d
10110110 dddd0000 zzzzvvvv ii...32...ii     leaq i(,z,v),d      i+z*v -> d
10110111 ddddssss zzzzvvvv ii...32...ii     leaq i(s,z,v),d     i+s+z*v -> d
-
1111cccc dddd0000 ii...32...ii pp...32...pp cb<c> $i,d,p        compare and continue at p if... (see below)

Note: first 4 bits are called the "major opcode", next 4 bits are called the "minor opcode".

Explanations:

aaaa indicates the kind of arithmetic operation. All operate on full 64 bits:

0000 add  addition
0001 sub  subtraction
0010 and  bitwise and
0011 or   bitwise or
0100 xor  bitwise xor
0101 mul  unsigned multiplication
0110 sar  shift arithmetic right (preserve topmost bit)
0111 sal  shift arithmetic left (zero into lsb, do not preserve topmost bit)
1000 shr  shift (logical) right (zero into topmost bit)
1001 imul signed multiplication

d,s and z are registers:

0000 %rax     1000 %r8
0001 %rbx     1001 %r9
0010 %rcx     1010 %r10
0011 %rdx     1011 %r11
0100 %rbp     1100 %r12
0101 %rsi     1101 %r13
0110 %rdi     1110 %r14
0111 %rsp     1111 %r15

v is a scale factor encoded into the field vvvv in the form of a shift amount as follows:

vvvv v
0000 1
0001 2
0010 4
0011 8

ii...32...ii is a 32 bit signed immediate
pp...32...pp is a 32 bit target address

<c> is a condition mnemonic used in compare-and-branch. The compare-and-branch
instruction cb<c> is not part of the original x86 instruction set, but the
conditions in x86prime carry the same meaning as for x86.

Example: cble %rdi,%rbp,target     = if %rdi <= %rbp (signed) then jump to target

Encoding          Semantic
0000 e            Equal
0001 ne           Not equal
0010 <reserved>
0011 <reserved>
0100 l            less (signed)
0101 le           less or equal (signed)
0110 g            greater (signed)
0111 ge           greater or equal (signed)
1000 a            above (unsigned)
1001 ae           above or equal (unsigned)
1010 b            below (unsigned)
1011 be           below or equal (unsigned)
11xx <reserved>

Note that signed and unsigned comparisons are different.

call places the return address in a register instead of pushing it onto the stack.
ret returns to the address in a register instead of popping it from the stack.
returning to address 0 or to a negative address (bit 64 set) stops the machine.