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, H to X)

Test 1: uops

Code:

  fcvtnu x0, h0
  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)a9accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
20045414043253000100020002000180000522541541248327420002000200054154111100110000007311611538100010001000542542542542542
20045414043253000100020002000180000522541541248327420002000200054154111100110000007311611538100010001000542542542542542
20045414043253000100020002000180001522541541248327420002000200054154111100110000007311611538100010001000542542542542542
20045414043253000100020002000180001522541541248327420002000200054154111100110000007311611538100010001000542542542542542
20045414043253000100020002000180000522541541248327420002000200054154121100110000007311611538100010001000542542542542542
20045414043253000100020002000180000522541541248327420002000200054154111100110000007311611538100010001000542542542542542
20045414343253000100020002000180001522541541248327420002000200054154111100110000067311611538100010001000542542542542542
20045414043253000100020002000180001522541541248327420002000200054154111100110000007311611538100010001000542542542542542
20045414043253000100020002000180001522541541248327420002000200054154111100110000007311611538100010001000542542542542542
20045414043253000100020002000180000522541541248327420002000200054154111100110000007311611538100010001000542542542542542

Test 2: Latency 1->2 roundtrip

Code:

  fcvtnu x0, h0
  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)l2 tlb miss data (0b)18191e1f3f4f51schedule 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)l1d cache writeback (a8)a9acc2branch cond mispred nonspec (c5)cfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
302041300389740000001300231194172540100101002000010000100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100001000000000131012162212952510000100001000010100130039130039130039130039130039
302041300389740000901300231194172540100101002000010000100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100001000000020131013162212974310000100001000010100130039130039130039130040130039
3020413003897400001201300231194172540100101002000010000100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300381300391120201100991001010010000100001000000300131012162212952510000100001000010100130287130039130042130039130039
302041300409740000001300251195972540100101002000010000100200001000050062151231480250901300160130048130043125476312624630100200100002000020010000200001300381300381120201100991001010010000100001000000600131012162212952510000100001000010100130039130039130039130039130039
302041300389770000001300231194172540100101002000010000100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100001000000000131012162212952510000100001000010100130039130039130039130039130039
302041300389740000001300231194272540100101002000010000100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100001000000000131012162212953110000100001000010100130039130039130039130039130039
302041300389730000001300231194172540100101002000010000100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100001000000000131012162212952510000100001000010100130075130039130039130039130039
3020513003897400008101300231194172540100101002000010000100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100001000000000131013162212952510003100001000010100130039130039130039130039130039
302041300389740000001300231194172540100101002000010000100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100001000000000131012162212952510000100001000010100130039130039130039130039130039
302041300389740000001300231194172540100101002000010000100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100001000000000131012162212952510000100001000010100130039130039130039130039130039

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0038

retire uop (01)cycle (02)03l1i tlb fill (04)mmu table walk data (08)l2 tlb miss instruction (0a)l2 tlb miss data (0b)18191e1f3a3f4f51schedule 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)acc2branch cond mispred nonspec (c5)cfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
300241300389740000009001300231194172540010100102000010000102000010000506214979148000251130013013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001000100000000012701162212952510000100001000010010130039130039130213130039130039
30024130038974000000000130023119419135402061005120079100631423134116668762825321497387601323140132741132447126626194127672346392412080241212412083234011329271328573012002110910100101000010001000001340160413162213002510000100001000010010132745132997134269133316133196
3002413410910361011424259403432113270511953119040060100152002610000112069810735876214979149550041132228013350313272412687131262683001020100002000020100002000013003813003811200211091010010100001000100000000012702161112952510000100001000010010130039130039130039130039130039
300241300389740000000001300231194172540010100102000010000102000010000506214979148000250130013013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001000100000000012703161212952510000100001000010235130081130106130046130039130039
3002413003897400000012001300231194172540010100102000010000102000010000506214979148000250130013013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001000100000000012703163212952510000100001000010010130039130039130039130039130039
300241300389740000000001300231194172540010100102000010000102000010000506214979148000250130014013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001000100000000012703162312952510000100001000010010130039130039130039130039130039
300241300389740000000001300231194172540010100102000010000102000010000506214979148000250130013013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001000100000000012703163212952610000100001000010010130075130039130039130092130039
300241300389890000000001301101194172540010100102000010000102000010000506214979148000250130013013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001000100000000012703163212952510000100001000010010130039130039130039130039130039
300241300389740000000001300231194562540010100102000010000102000010000506214979148009580130013013003813004112549831262683001020100002000020100002000013003813003811200211091010010100001000100000000012702162212952510000100001000010010130039130039130039130039130039
300241300389740000000001300231194172540010100102000010000102000010000506214979148000250130013013003813003812549831262683001020100002000020100002000013003813003811200211091010010100001000100000000012702162212952510000100001000010010130039130039130041130039130040

Test 3: throughput

Count: 8

Code:

  fcvtnu x0, h8
  fcvtnu x1, h8
  fcvtnu x2, h8
  fcvtnu x3, h8
  fcvtnu x4, h8
  fcvtnu x5, h8
  fcvtnu x6, h8
  fcvtnu x7, h8
  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)03mmu table walk data (08)191e3f51schedule 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 cache writeback (a8)acbranch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)fetch restart (de)e0? int output thing (e9)eb? simd retires (ee)? int retires (ef)f5f6f7f8fd
160204400663100003225240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100653111511711604003880000080000801004004240042400424004240042
16020440041310000322524010480100160004100160020500144013204002240041400411997761999216012020016003220016003240041400411180201100991008010010003111511701604003880000080000801004004240042400424004240042
160204400413210003225240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100320111511701604003880000080000801004004240042400424004240042
160204400413100003225240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100380111511701604003880000080000801004004240042400424004240042
160204400413100003225240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100440111511701604003880000080000801004004240042400424004240042
16020440041310000322524010480100160004100160020500144013204002240041400411997761999216012020016003220016003240041400411180201100991008010010076111511701604003880000080000801004004240042400424004240042
1602044004131000369725240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100380111511701604003880000080000801004004240042400424004240042
160204400413110003225240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100590111511701604003880000080000801004004240042400424004240042
160204400413100003225240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100540111511701604003880000080000801004004240042400424004240042
16020440041311000322524010480100160004100160020500144013204002240041400411997761999216012020016003220016003240041400411180201100991008010010093111513201604003880000080000801004004240042400424004240042

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)03mmu table walk instruction (07)mmu table walk data (08)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)5f6061696d6emap 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)9fld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9acc2cfd2d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1600244005531000000120126252400108001016000010160000501440000000400224004140041199963200211600102016000020160000400414004111800211091080010100000005020012161516400388000080000800104004240042400424004240042
160024400413100000000422524001080010160000101600005014400000004002240041400411999634200211600102016000020160000400414004111800211091080010100030005020016161512400388000080000800104004240042400424004240042
160024400413100000024042252400108001016000010160000501440000000400224004140041199963200711600102016000020160000400414004111800211091080010100000005020013161311400388000080000800104004240042400424004240042
16002440041310000006042252408688001016000010160000501440000005400224004140041199963200211600102016000020160000400414004111800211091080010100010305020015161310400388000080000800104004240042400424004240042
160024400413100000000707252400108001016000010160000501443542105400224004140041199963200211600102016000020160000400414004111800211091080010100000005020013161415400388000080000800104004240042400424004240042
16002440041311000000084252400108001016000010160000501440000000400224004140041199963200211600102016000020160000400414004111800211091080010100040305020015161313400388000080000800104004240361400424004240042
160024400413100000000422524001080010160000101600005014400000004002240041400411999632200211600102016000020160000400414004111800211091080010100000005020011161613400388000080000800104004240042400424004240042
16002440041310000010042252400108001016000010160000501447000000400224004140041199963200211600102016000020160000400414004111800211091080010100000005020012161314400388000080000800104004240042400424004240042
160024400413100000012042252400108001016000010160000501440000000400224004140041199963200211600102016000020160000400414004111800211091080010100000005020017161215400388000080000800104004240042400424004240042
16002440041310000000042252400108001016000010160000501440000000400224004140041199963200211600102016000020160000400414004111800211091080010100000005020013161415400388000080000800104004240042400424004240042