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

FCVTNU (scalar, S to X)

Test 1: uops

Code:

  fcvtnu x0, s0
  mov x0, 1
  mov x1, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 2.000

Issues: 3.000

Integer unit issues: 1.000

Load/store unit issues: 0.000

SIMD/FP unit issues: 2.000

retire uop (01)cycle (02)031e3f51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch simd uop (57)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map simd uop (7e)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst int alu (97)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
2004541405125300010002000200018000052254154124832742000200020005415411110011000007341622538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007321622538100010001000542542542542542

Test 2: Latency 1->2 roundtrip

Code:

  fcvtnu x0, s0
  fmov d0, x0
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 13.0038

retire uop (01)cycle (02)03mmu table walk data (08)0918191e1f3a3f4f51schedule uop (52)schedule int uop (53)schedule simd uop (54)schedule ldst uop (55)dispatch int uop (56)dispatch simd uop (57)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)ldst uops in schedulers (5b)60696b6d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map ldst uop (7d)map simd uop (7e)map int uop inputs (7f)map ldst uop inputs (80)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d tlb access (a0)l1d tlb miss (a1)ld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9acc2branch cond mispred nonspec (c5)cdcfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
302041300389740000000130023119417254010010100200001000010020000100005006214979148010341130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000000000131002162212952510000100001000010100130039130039130039130039130039
30204130038974000021001300231194172540100101002000010000100200001000050062149791480103411300130130038130038125476151262333010020010000200002001000020000130040130038112020110099100101001000010000100000000000131003162312952510000100001000010100130039130039130039130039130039
302041300389740000000130023119423254010010100200001000010020000100005006214979148010341130013013003813007412547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000000010131001163312952510000100001000010100130039130039130039130039130039
3020413003810080100000130023119417254010010100200001000010020000100005006214979148010340130013013003813003812547631262473010020010000200002001000020000130038130038112020110099100101001000010000100000000000131002162312952510000100001000010100130039130039130039130039130039
3020413003897400001200130023119417254010010100200001000010020000100005006214979148010341130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010002100040103400131003163312952510000100001000010100130041130039130039130039130039
302041300389740000000130023119417254010010100200001000010020000100005006214979148010341130013013003813003812547831262463010020010000200002001000020000130040130038112020110099100101001000010000100000103000131003163312952510000100001000010100130039130039130039130039130039
302041300709740040000130023119417384010010100200001000010020000100005006214979148011460130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000000000131003163312952510000100001000010100130039130039130039130039130039
3020413003897400003000130023119417254010010100200001000010020000100005006214979148010341130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000000000131002163212952510000100001000010100130039130039130039130039130039
302041300389740000000130065119417254010010100200001000010020000100005006215445148041041130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000003000131003163312952510000100001000010100130039130039130039130039130039
302041300389740000000130023119417254010010100200001000010020000100005006214979148010340130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000000000131002163312952510000100001000010100130039130039130039130039130039

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0038

retire uop (01)cycle (02)03mmu table walk instruction (07)1e3f4f51schedule uop (52)schedule int uop (53)schedule simd uop (54)schedule ldst uop (55)dispatch int uop (56)dispatch simd uop (57)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)ldst uops in schedulers (5b)60696b6d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map ldst uop (7d)map simd uop (7e)map int uop inputs (7f)map ldst uop inputs (80)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fld unit uop (a6)l1d cache writeback (a8)a9acbranch mispred nonspec (cb)cfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30024130038974001300231194172540010100102000010000102000010000506214979148000250130013013007413006212549831262683001020100002000020100002013213003913004011200211091010010100001010000000012705161112952510000100001000010010130039130039130039130039130039
30024130038974001301041194192540010100102000010000102000010000506214979148000250130013013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001010000000012701162112952510000100001000010010130077130039130039130039130039
30024130038974001300231194172540010100102000410000102000010000506214979148001370130013013003813003812549831262683001020100002012320100002000013003813003811200211091010010100001010000000012701161212952510000100001000010010130039130039130039130039130039
300241300389740013002311941725400101001020000100001020000100005062149791480002501300130130038130038125498191263163001020100002000020100002000013003813003811200211091010010100001010000000012701161112952510000100001000010010130039130039130039130039130039
30024130038974001300231194172540010100102000010000102000010000506214979148000250130013013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001010000000012701161112952510000100001000010010130039130039130039130039130039
30024130038974091300231194172540010100102000010000102000010000506214979148000250130019013003813003812549831262683001020100002000020100002000013003913003811200211091010010100001010000000012701161112952510000100001000010010130039130039130039130070130039
30024130038974091300231194172540010100102000010000102000010000506214979148000251130013013003813003812549831262683001020100002000020100002000013003813006011200211091010010100001010000000012701161112952510000100001000010010130039130039130039130039130039
30024130038974001300231194172540010100102000010000102000010000506214979148000250130013013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001010000000112701161112952510000100001000010010130039130039130039130041130039
300241300389740691300231194172540010100102000010000102000010000506214979148000250130013013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001010000000012701161112952510000100001000010010130039130039130039130039130039
30024130038974001300231194172540010100102000010000102000010000506214979148000250130013013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001010000000012703161112952510000100001000010010130039130039130039130039130039

Test 3: throughput

Count: 8

Code:

  fcvtnu x0, s8
  fcvtnu x1, s8
  fcvtnu x2, s8
  fcvtnu x3, s8
  fcvtnu x4, s8
  fcvtnu x5, s8
  fcvtnu x6, s8
  fcvtnu x7, s8
  mov x8, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.5005

retire uop (01)cycle (02)03181e3f5051schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)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 access (a0)l1d tlb miss (a1)l1d cache writeback (a8)acc2branch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
160204400643000032400252524010480100160004100160020500144013204002240041400411997761999216012020016003220016003240041400411180201100991008010010000000111511721612400388000080000801004004240042400424004240042
16020440041300303202524010480100160004100160020500144013204002240041400411997761999216012020016003220016003240041400411180201100991008010010000000111511711622400388000080000801004004240042400424004240042
16020440041300003202524010480100160004100160020500144013214002240041400411997761999216012020016003220016003240041400411180201100991008010010000000111511711612400388000080000801004004240042400424004240042
16020440041300003202524010480100160004100160020500144013214002240041400411997761999216012020016003220016003240041400411180201100991008010010000000111511721622400388000080000801004004240042400424004240042
16020440041299003202524010480100160004100160020500144013204002240041400411997761999216012020016003220016003240041400411180201100991008010010000000111511721621400388000080000801004004240042400424004240042
16020440041299005302524010480100160004100160020500144013214002240041400411997761999216012020016003220016003240041400411180201100991008010010000000111511721621400388000080000801004004240042400424004240042
16020440041300003202524010480100160004100160020500144013204002240041400411997761999216012020016003220016003240041400411180201100991008010010000090111511721622400388000080000801004004240042400424004240042
16020440041299003202524010480100160004100160020500144013204002240041400411997761999216012020016003220016003240041400411180201100991008010010000000111511711612400388000080000801004004240042400424004240042
16020440041300003202524010480100160004100160020500144013204002240041400411997761999216012020016003220016003240041400411180201100991008010010000000111511721621400388000080000801004004240042400424004240042
16020440041300003202524010480100160004100160020500144013214002240041400411997761999216012020016003220016003240041400411180201100991008010010000000111511721622400388000080000801004004240042400424004240042

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.5005

retire uop (01)cycle (02)03mmu table walk data (08)l2 tlb miss instruction (0a)l2 tlb miss data (0b)18191e1f3f51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)6061696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)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 access (a0)l1d tlb miss (a1)l1d cache writeback (a8)a9accfd2d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
16002440042299000000042252400108001016000010160000501440000004002240041400411999632002116001020160000201600004004140041118002110910800101000006502001416106400388000080000800104004240042400424004240042
160024400413000000000422524001080010160000101600005014400000040022400414004119996320021160010201600002016000040041400411180021109108001010000005020014161213400388000080000800104004240042400424004240042
16002440041300000000042252400108001016000010160000501440000004002240041400411999632002116001020160000201600004004140041118002110910800101000000502007351411400388000080000800104004240042400424004240042
1600244004130000000004225240010800101600001016000050144000000400224004140041199963200211600102016000020160000400414004111800211091080010100000216502001016107400388000080000800104004240042400424004240042
1600244004130000000004225240010800101600001016000050144000000400224004140041199963200211600102016000020160000400414004111800211091080010100000335020012161010400388000080000800104004240042400424004240042
16002440041300000000042252400108001016000010160000501440000004002240041400411999632002116001020160000201600004004140041118002110910800101000000502011216117400388000080000800104004240042400424004240042
160024400412990000000422524001080010160000101600005014400000040022400414004119996320021160646201600002016000040041400411180021109108001010000005020010161211400388000080000800104004240042400424004240042
1600244004130000000001912524001080010160000101600005014400000040022400414004119996320021160010201600002016000040041400411180021109108001010000005020010161010400388000080000800104004240042400424004240042
160024400413000000000422524001080010160000101600005014400000040022400414010719996320021160226201600002016000040041400411180021109108001010000005020011161010400388000080000800104004240042400424004240042
1600244004130000000008425240010800101600001016000050144000000400224004140041199963200211600102016000020160000400414004111800211091080010100000050200616711400388000080000800104004240042400424004240042