CSCI 370: Computer Architecture
Y86-64 Reference
Instruction Format
0 0
1 0
9 0
2 0 rA rB
2fn rA rB
6 0 rA rB
6 1 rA rB
6 2 rA rB
6 3 rA rB
A 0 FrA
B 0 FrA
8 0 Dest
7fn Dest
7 0 Dest
5 0 rA rB D
4 0 rA rB D
3 0 F rB V
halt
nop
rrmovq rA, rB
cmovXX rA, rB
irmovq V, rB
rmmovq rA,D(rB)
mrmovq D(rB),rA
addq rA, rB
subq rA, rB
andq rA, rB
xorq rA, rB
jmp Dest
jXX Dest
call Dest
ret
pushq rA
popq rA
1
2
3
4
5
6
le
l
e
ne
ge
g
fn Codes
icode,ifun
rA,rB
valC
valP
valA,srcA
valB,srcB
valE
cnd
valM
dstE
dstM
PC
Fetch
Decode
Execute
Memory
Writeback
PC Update
Read instruction byte
Read register byte
Read constant word
Compute next PC
Read operand A
Read operand B
Perform ALU operation
Set/Use Condition Code
Memory Read/Write
Write back ALU result
Write back Mem result
Update PC
register(s) descriptionstage
HCL Y86-64 Hardware Registers
Registers
%rdi
%rsi
%rdx
%rcx
%r8
%r9
%rax
%rbx
%r10
%r11
%r12
%r13
%r14
%rsp
%rbp
F
5
4
E
D
C
3
B
A
0
9
8
1
2
6
7arg1
arg2
arg3
arg4
arg5
arg6
return
stack ptr
base ptr
no reg
caller-savedcallee-saved
ID Enc Usage
general
general
general
general
general
general
.align 8
Array:
.quad 0x0000000000000001
.quad 0x0000000000000002
.quad 0x0000000000000003
.quad 0x0000000000000004
Y86-64 Data Example
AOK
HLT
ADR
INS
1
2
3
4
Normal
Halt Encountered
Bad Address
Invalid Instruction
Status Conditions
/* find number of elements in null-terminated list */
long len(long* a) {
long len;
for (len = 0; a[len]; ++len)
;
return len;
}
len:
irmovq $1, %r8 # Constant 1
irmovq $8, %r9 # Constant 8
irmovq $0, %rax # len = 0
mrmovq (%rdi), %rdx # val = *a
and %rdx, %rdx # Test val
je Done # If zero, goto Done
Loop:
addq %r8, %rax # len++
addq %r9, %rdi # a++
mrmovq (%rdi), %rdx # val = *a
andq %rdx, %rdx # Test val
jne Loop # If !0, goto Loop
Done:
ret
Assembly Translation Example
