Apple Microarchitecture Research by Dougall Johnson

M1/A14 P-core (Firestorm): Overview | Base Instructions | SIMD and FP Instructions
M1/A14 E-core (Icestorm):  Overview | Base Instructions | SIMD and FP Instructions

SUB (uxtw, 32-bit)

Test 1: uops

Code:

  sub w0, w0, w1, uxtw
  mov x0, 1
  mov x1, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 1.000

Integer unit issues: 1.001

Load/store unit issues: 0.000

SIMD/FP unit issues: 0.000

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
100410301001100110002560310001000200010011000
100410301001100110002560310001000200010011000
100410301001100110002560310001000200010011000
100410301001100110002560310001000200010011000
100410301001100110002560310001000200010011000
100410301001100110002560310001000200010011000
100410301001100110002560310001000200010011000
100410301001100110002560310001000200010011000
100410301001100110002560310001000200010011000
100410301001100110002560310001000200010011000

Test 2: Latency 1->2

Code:

  sub w0, w0, w1, uxtw
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
10204100301010110101101072595391010710213202281000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100

1000 unrolls and 10 iterations

Result (median cycles for code): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
10024100301002110021100282598461007010082200521001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202600511006410066200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010

Test 3: Latency 1->3

Code:

  sub w0, w1, w0, uxtw
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
10204100301010110101101072595391010710212202281000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710213202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100
10204100301010110101101072595391010710212202241000110100

1000 unrolls and 10 iterations

Result (median cycles for code): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
10024100301002110021100282595281003010038200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010
10024100301002110021100202595911002010020200201001110010

Test 4: throughput

Count: 8

Code:

  sub w0, w8, w9, uxtw
  sub w1, w8, w9, uxtw
  sub w2, w8, w9, uxtw
  sub w3, w8, w9, uxtw
  sub w4, w8, w9, uxtw
  sub w5, w8, w9, uxtw
  sub w6, w8, w9, uxtw
  sub w7, w8, w9, uxtw
  mov x8, 9
  mov x9, 10

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.3342

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
802042690580115801158012024036080120802221602448001580100
802042675380115801158012024036080120802241602488001580100
802042673780115801158012024036080120802241602488001580100
802042673780115801158012024036080120802241602488001580100
802042673780115801158012024036080120802241602488001580100
802042673780115801158012024036080120802241602488001580100
802042673780115801158012024036080120802241602488001580100
802042673780115801158012024036080120802241602488001580100
802042673780115801158012024036080120802241602488001580100
802042673780115801158012024036080120802241602488001580100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.3339

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
800242796180039800398004426147780042800461600208001180010
800242679080021800218002028273880020800201600208001180010
800242671380021800218002027740480020800201600208001180010
800242672180021800218002028273880020800201600208001180010
800242687280130801308012928273880020800201600748002980010
800242674680021800218002027740480020800201600208001180010
800242672480021800218002028273880020800201600208001180010
800242672480021800218002028273880020800201600208001180010
800242686980021800218002027740480020800201600208001180010
800242696080181801818018027207180020800201600208001180010