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

CMN (uxtb, 64-bit)

Test 1: uops

Code:

  cmn x0, w1, uxtb
  mov x0, 1
  mov x1, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 2.000

Integer unit issues: 2.001

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)
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001

Test 2: Latency 3->1

Chain cycles: 1

Code:

  cmn x0, w1, uxtb
  cset x0, cc
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code, minus 1 chain cycle): 2.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)dispatch uop (78)map int uop (7c)map ldst uop (7d)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
20204300303010130101201050789247020108202140302153000110100
20204300303010130101201050789369020105202120302183000110100
20204300303010130101201050789369020105202120302183000110100
20204300303010130101201050789369020105202120302183000110100
20205300603011530115201400789369020105202120302183000110100
20204300303010130101201050789369020105202120302843001510100
20204300303010130101201050789369020105202120302183000110100
20204300303010130101201050789369020105202120302183000110100
20204300303010130101201050789369020105202120302183000110100
20204300303010130101201050789369020105202120302183000110100

1000 unrolls and 10 iterations

Result (median cycles for code, minus 1 chain cycle): 2.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule ldst uop (55)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)
200243003030011300110200157894382001020020300203000110010
200243003030011300110200107894382001020020300203000110010
200243003030011300110200107894382001020020300203000110010
200243003030011300110200107894382001020020300203000110010
200243003030011300110200107894382001020020300203000110010
200243003030011300110200107894382001020020300203000110010
200243003030011300110200107894382001020020300203000110010
200243003030011300110200107894382001020020300203000110010
200243003030011300110200107897732004520062300203000110010
200243003030011300110200107894382001020020300203000110010

Test 3: Latency 3->2

Chain cycles: 1

Code:

  cmn x0, w1, uxtb
  cset x1, cc
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code, minus 1 chain cycle): 2.0030

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)
20204300303010130101201067892182010720214302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100

1000 unrolls and 10 iterations

Result (median cycles for code, minus 1 chain cycle): 2.0030

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)
20024300303001130011200157893802001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300833001510010

Test 4: throughput

Count: 8

Code:

  cmn x0, w1, uxtb
  cmn x0, w1, uxtb
  cmn x0, w1, uxtb
  cmn x0, w1, uxtb
  cmn x0, w1, uxtb
  cmn x0, w1, uxtb
  cmn x0, w1, uxtb
  cmn x0, w1, uxtb
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.6675

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)
80204534081601171601178012711775838012580226160248160014100
80204534021601141601148012311776278012380224160248160014100
80204534021601141601148012311779208016680268160336160065100
80204534021601141601148012311776278012380224160248160014100
80204534021601141601148012311776358012380224160248160014100
80204534021601141601148012311776198012380224160248160014100
80204534021601141601148012311776358012380224160248160014100
80204534021601141601148012311776318012380224160248160014100
80204534021601141601148012311776558012380224160248160014100
80204534021601141601148012311776198012380224160248160014100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.6671

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)
8002453376160036160036800451170309800478004816002016001110
8002453371160021160021800201170032800208002016002016001110
8002453371160021160021800201170032800208002016002016001110
8002453371160021160021800201170032800208002016002016001110
8002453371160021160021800201170032800208002016002016001110
8002453371160021160021800201170032800208002016002016001110
8002453371160021160021800201170032800208002016002016001110
8002453371160021160021800201170032800208002016002016001110
8002453371160021160021800201170032800208002016002016001110
8002553408160084160084800871170032800208002016002016001110