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

CLZ (32-bit)

Test 1: uops

Code:

  clz w0, w0
  mov x0, 1
  mov x1, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 1.000

Integer unit issues: 1.000

Load/store unit issues: 0.000

SIMD/FP unit issues: 0.000

retire uop (01)cycle (02)031e3f4d51schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)606d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map int uop inputs (7f)8283flush restart other nonspec (84)85inst all (8c)inst int alu (97)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? int retires (ef)f5f6f7f8fd
100410358061862251000100010001691611035103572838681000100010001035411110011000073241119371000100010361036103610361036
100410358061862251000100010001691601035103572838681000100010001035411110011000073141119371000100010361036103610361036
100410358061862251000100010001691601035103572838681000100010001035411110011000073141119371000100010361036103610361036
100410357061862251000100010001691601035103572838681000100010001035411110011000073141119371000100010361036103610361036
100410358061862251000100010001691601035103572838681000100010001035411110011000073141119371000100010361036103610361036
100410358061862251000100010001691601035103572838681000100010001035411110011000073141119371000100010361036103610361036
100410357061862251000100010001691601035103572838681000100010001035411110011000073141119371000100010361036103610361036
100410358061862251000100010001691601035103572838681000100010001035411110011000073141119371000100010361036103610361036
100410358061862251000100010001691601035103572838681000100010001035411110011000073141119371000100010361036103610361036
100410357061862251000100010001691601035103572838681000100010001035411110011000073141119371000100010361036103610361036

Test 2: Latency 1->2

Code:

  clz w0, w0
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 1.0035

retire uop (01)cycle (02)03mmu table walk instruction (07)l2 tlb miss instruction (0a)1e3f4d51schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)696a6d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map int uop inputs (7f)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)9facbranch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? int retires (ef)f5f6f7f8fd
10204100357511061987725101001010010117876864969551003510035860778734101171024010240100354111102011009910010100100011172011611996810000101001003610036100361003610036
10204100357511061987725101001010010117876864969551003510035860778734101171024010240100354111102011009910010100100011172011611996810000101001003610036100361003610036
10204100357511061987725101001010010100886644969551003510035858038722101001020010200100354111102011009910010100100000071023722994110000101001003610036100361003610036
10204100357500961987725101001010010100886644969551003510035858038722101001020010200100354111102011009910010100100000071023722994110000101001003610036100361003610036
10204100357500061987725101001010010100886644969551003510035858038722101001020010200100354111102011009910010100100000071023722994110000101001003610036100361003610036
10204100357500061987725101001010010100886644969551003510035858098722101001020010200100354111102011009910010100100000071023722994110000101001003610036100361003610036
10204100357500061987725101001010010100886644969551003510035858038722101001020010200100354111102011009910010100100000071023722994110000101001003610036100361003610036
10204100357500061987725101001010010100886644969551003510035858038722101001020010200100354111102011009910010100100000071023722994110000101001003610036100361003610036
10204100357500066987725101001010010100886644969551003510035858038722101001020010200100354111102011009910010100100000071023722994110000101001003610036100361003610036
10204100357500061987725101001010010100886644969551003510035858038722101001020010200100354111102011009910010100100000071023722994110000101001003610036100361003610036

1000 unrolls and 10 iterations

Result (median cycles for code): 1.0035

retire uop (01)cycle (02)03191e3f4d51schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)696a6d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map int uop inputs (7f)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)9fst unit uop (a7)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? int retires (ef)f5f6f7f8fd
1002410035750061986325100101005610010887844969551003510035860238740100101002010020100354111100211091010010100064024122994010000100101003610036100361003610036
10024100357502461986325100101001010010887844969551003510035860238740100101002010020100354111100211091010010100064024122994010000100101003610036100361003610036
1002410035750061986325100101001010010887844969551003510035860238740100101002010020100354111100211091010010100064024122994010000100101003610036100361003610036
1002410035750061986325100101001010010887844969551003510035860238740100101002010020100354111100211091010010100064024122994010000100101003610036100361003610036
10024100357502461986325100101001010010887844969551003510035860238740100101002010020100354111100211091010010100064024122994010000100101003610036100361003610036
1002410035750061986325100101001010010887844969551003510035860238740100101002010020100354111100211091010010100064024122994010000100101003610036100361003610036
1002410035750061986325100101001010010887844969551003510035860238740100101002010020100354111100211091010010100064024122994010000100101003610036100361003610036
10024100357502461986325100101001010010887844969551003510035860238740100101002010020100354111100211091010010100064024122994010000100101003610036100361003610036
10024100357502161986325100101001010010887844969551003510035860238740100101002010020100354111100211091010010100064024122994010000100101003610036100361003610036
10024100357502461986325100101001010010887844969551003510035860238740100101002010020100354111100211091010010100064024122994010000100101003610036100361003610036

Test 3: throughput

Count: 8

Code:

  clz w0, w8
  clz w1, w8
  clz w2, w8
  clz w3, w8
  clz w4, w8
  clz w5, w8
  clz w6, w8
  clz w7, w8
  mov x8, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.1674

retire uop (01)cycle (02)03mmu table walk data (08)1e1f3f51schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)60696a6d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map int uop inputs (7f)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)9fst unit uop (a7)l1d cache writeback (a8)acbranch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? int retires (ef)f5f6f7f8fd
8020413414100000282780136801368014840071004910371133901339033266333680148802648026413390391180201100991008010010000421115119216221338780036801001339113391133911339113391
802041339010000028278013680136801484007100491031013390133903326633368014880264802641339039118020110099100801001000001115120216211338780036801001339113391133911339113391
802041339010002190382780136801368014840071004910310133901339033266333680148802648026413390391180201100991008010010000871115120216221338780036801001339113391133911339113391
802041339010000028278013680136801484007101491031013390133903326633368014880264803921339039118020110099100801001000001115120216221338780036801001339113391133911339113391
802041339010000028278013680136801484007100491031013390133903326633368014880264802641339039118020110099100801001000001115120116221338780036801001339113391133911339113391
802041339010000028278013680136801484007100491031013390133903326633368014880264802641339039118020110099100801001000001115120216211338780036801001339113391133911339113391
802041339010000028278013680136801484007100491031013390133903326633368014880264802641339039118020110099100801001000001115120116211338780036801001339113391133911339113391
802041339010000028278013680136801484007100491031013390133903326633368014880264802641339039118020110099100801001000001115120216211338780036801001339113391133911339113391
8020413390100066028278013680136801484007100491031013390133903326633368014880264802641339039118020110099100801001000001115120216221338780036801001339113391133911339113391
802041339010000028278013680136801484007100491031013390133903326633368014880264802641339039118020110099100801001000001115120216221338780036801001339113391133911339113391

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.1671

retire uop (01)cycle (02)03181e3a3f51schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)5f60696a6d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map int uop inputs (7f)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)9fl1d tlb miss (a1)ld unit uop (a6)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? int retires (ef)f5f6f7f8fd
8002413377101000352580010800108001040005001491029113371133713330333488001080020800201355239118002110910800101000005021519771336880000800101337213372133721337213372
80024133711000120352580010800108001040005001491029113371133713330333488001080020800201337139118002110910800101000005020319541336880000800101337213372133721337213372
8002413371100000352580010800108001040005001491029113371133713330333488001080020800201337139118002110910800101000005021419431336880000800101337213372133721337213372
8002413371101000352580010800108001040005001491029113371133713330333488001080020800201337139118002110910800101000005020419531336880000800101337213372133721337213372
8002413371100000352580010800108001040005001491029113371133713330333488001080020800201337139118002110910800101000005020419661336880000800101337213372133721337213372
80024133711000120352580010800108001040005001491029113371133713330333488001080020800201337139118002110910800101000005020419641336880000800101337213372133721337213372
80024133711000120352580010800108001040005001491029113371133713330333488001080020800201337139118002110910800101000005020419341336880000800101337213372133721337213372
8002413371100000772580010800108001040005011491029113371133713330333488001080020800201337139118002110910800101000005020419771336880000800101337213372133721337213372
8002413371100000352580010800108001040005001491029113371133713330333488001080020800201337139118002110910800101000005021719341336880000800101337213372133721337213372
8002413371100000352580010800108001040005001491029113371133713330333488001080020800201337139118002110910800101000005020419431336880000800101337213372133721337213372