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

RBIT (64-bit)

Test 1: uops

Code:

  rbit x0, x0
  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)03l2 tlb miss data (0b)1e3f4d51schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)6d6emap 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)l1d tlb access (a0)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? int retires (ef)f5f6f7f8fd
10041035700618622510001000100016916103510357283868100010001000103541111001100000073341119371000100010361036103610361036
10041035700618622510001000100016916103510357283868100010001000103541111001100000073141119371000100010361036103610361036
10041035800618622510001000100016916103510357283868100010001000103541111001100000073141119371000100010361036103610361036
10041035800618622510001000100016916103510357283868100010001000103541111001100000073141119371000100010361036103610361036
10041035800618622510001000100016916103510357283868100010001000103541111001100000073141119371000100010361036103610361036
10041035700618622510001000100016916103510357283868100010001000103541111001100000073141119371000100010361036103610361036
100410357001188622510001000100016916103510357283868100010001000103541111001100000073141119371000100010361036103610361036
10041035700618622510001000100016916103510357283868100010001000103541111001100000073141119371000100010361036103610361036
10041035710618622510001000100016916103510357283868100010001000103541111001100000073141119571000100010361036103610361036
10041035700618622510001000100016916103510357283868100010001000103541111001100000073141119371000100010361036103610361036

Test 2: Latency 1->2

Code:

  rbit x0, x0
  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)031e3f4d51schedule 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)9fl1d tlb miss (a1)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? int retires (ef)f5f6f7f8fd
1020410035758761987725101001010010100886641496955100351003585803872210100102001020010035411110201100991001010010000071013711994110000101001003610036100361003610036
1020410035750166987725101001010010100886641496955100351003585803872210100102001020010035411110201100991001010010000071013711994110000101001003610036100361003610036
102041003575361987725101001010010100886640496955100351003585803872210100102001020010035411110201100991001010010000071013711994110000101001003610036100361003610036
102041003575061987725101001010010100886641496955100351003585803872210100102001020010035411110201100991001010010000071014711994110000101001003610036100361003610036
102041003575061987725101001010010100886641496955100351003585803872210100102001020010035411110201100991001010010000071013711994110000101001003610036100361003610036
10204100357518661987725101001010010100886641496955100351003585803872210100102001020010035411110201100991001010010000071023711994110000101001003610036100361003610036
102041003575061987725101001010010100886641496955100351003585803872210100102001020010035411110201100991001010010000071013711994110000101001003610036100361003610036
102041003575061987725101001010010100886641496955100811003585803872210269102001020010035411110201100991001010010000123871013711994110000101001003610036100361003610036
102041003575061987725101001010010100886641496955100351003585803872210100102001020010035411110201100991001010010000071013711994110000101001003610036100361003610036
102041003575061987725101001010010100886641496955100351003585803872210100102001020010035411110201100991001010010040071013711994110000101001003610036100361003610036

1000 unrolls and 10 iterations

Result (median cycles for code): 1.0035

retire uop (01)cycle (02)03mmu table walk data (08)191e3f4d51schedule 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)9fcfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? int retires (ef)f5f6f7f8fd
100241003575000619863251001010010100108878449695510035100358602387401001010020100201003541111002110910100101064024122994010000100101003610036100361003610036
100241003575000619863251001010010100108878449695510035100358602387401001010020100201003541111002110910100101064024122994010000100101003610036100361003610036
100241003575010619863251001010010100108878449695510035100358602387401001010020100201003541111002110910100101064024122994010000100101003610036100361003610036
100241003575000619863251001010010100108878449695510035100358602387401001010020100201003541111002110910100101064024122994010000100101003610036100361003610036
100241003575000619873251001010010100108878449695510035100358602387401001010020100201003541111002110910100101064024122994010000100101003610036100361003610036
100241003575000619863251001010010100108878449695510035100358602387401001010020100201003541111002110910100101064024122994010000100101003610036100361003610036
100241003575000619863251001010010100108878449695510035100358602387401001010020100201003541111002110910100101064024122994010000100101003610036100361003610036
100241003575000619863251001010010100108878449695510035100358602387401001010020100201003541111002110910100101064024122994010000100101003610036100361003610036
100241003575000619863251001010010100108878449695510035100358602387401001010020100201003541111002110910100101064024122994010000100101003610036100361003610036
100241003575000619863251001010010100108878449695510035100358602387401001010020100201003541111002110910100101064024122994010000100101003610036100361003610036

Test 3: throughput

Count: 8

Code:

  rbit x0, x8
  rbit x1, x8
  rbit x2, x8
  rbit x3, x8
  rbit x4, x8
  rbit x5, x8
  rbit x6, x8
  rbit x7, x8
  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)031e3a3f51schedule 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)9fl1d tlb miss (a1)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
80204134141046002827801368013680148400710491031013390133903326633368014880264802641339039118020110099100801001000001115120216001338780036801001339113391133911339113391
8020413390100002827801368013680148400710491031013390133903326633368014880264802641339039118020110099100801001000001115119016001338780036801001339113391133911339113391
8020413390101002827801368013680148400710491031013390133903326633368014880264802641339039118020110099100801001000001115119016001338781118801001339113391133911339113391
8020413390100002827801368013680148400710491031013390133903326633368014880264802641339039118020110099100801001000001115119016001338780036801001339113391133911339113391
8020413390101002827801368013680148400710491031013390133903326633368014880264802641339039118020110099100801001000001115119016001338780292801001339113391133911339113391
8020413390108002827801368013680148400710491031013390133903326633368014880264802641339039118020110099100801001000001115119016001338780036801001339113391133911339113391
8020413390100002827801368013680148400710491031013390133903326633368014880264802641339039118020110099100801001000001115119016001338780036801001339113391133911339113391
8020413390100002827801368013680148400710491031013390133903326633368014880264802641339039118020110099100801001000001115119016001338780036801001339113391133911339113391
8020413390100002827801368013680148400710491031013390133903326633368014880264802641339039118020110099100801001000001115119016001338780036801001339113391133911339113391
80204133901017202827801368013680148400710491031013390133903326633368014880264802641339039118020110099100801001000001115120016001338780036801001339113391133911339113391

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)031e3f51schedule 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)9fl1d cache writeback (a8)cfd0d5map dispatch bubble (d6)daddfetch restart (de)e0? int output thing (e9)? int retires (ef)f5f6f7f8fd
800241337710103525800108001080010400050049102911337113371333033348800108002080020133713911800211091080010100502108190461336880000800101337213372133721337213372
800241337110003525800108001080010400050049102911337113371333033348800108002080020133713911800211091080010100502304190771336880000800101337213372133721337213372
800241337110003525800108001080010400050049102911337113371333033348800108002080020133713911800211091080010100502204190461336880126800101337213372133721337213372
800241337110063525800108001080010400050049102911337113371333033348800108002080020133713911800211091080010100502305190661336880000800101337213372133721337213372
800241337110003525800108001080010400050049102911337113371333033348800108002080020133713911800211091080010100502108190641336880000800101337213372133721337213372
8002413371100051025800108001080010400050049102911337113371333033348800108002080020133713911800211091080010100502405190471336880000800101337213372133721337213372
800241337110003525800108001080010400050049102911337113371333033348800108002080020133713911800211091080010100502306190641336880000800101337213372133721337213372
800241337110005625800108001080010400050049102911337113371333033348800108002080020133713911800211091080010100502206190461336880000800101337213372133721337213372
800241337110063525800108001080010400050049139221337113371333033348800108002080020133713911800211091080010100502407190771336880000800101337213372133721337213372
8002413371100016325800108001080010400050149102911337113371333033348800108002080020133713911800211091080010100502206190461336880000800101337213372133721337213372