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

FCVTNS (scalar, D to W)

Test 1: uops

Code:

  fcvtns w0, d0
  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)03mmu table walk data (08)1e3f51schedule 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)a9acc2cfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
2004541400432530001000200020001800005225415412483274200020002000541541111001100010007311611538100010001000542542542542542
2004541400432530001000200020001800005225415412483274200020002000541541111001100000007311611538100010001000542542542542542
2004541400432530001000200020001800005225415412483274200020002000541541111001100000007311611538100010001000542542542542542
2004541400432530001000200020001800015225415412483274200020002000541541111001100000007311611538100010001000542542542542542
20045414012432530001000200020001800005225415412483274200020002000541541111001100000307311611538100010001000542542542542542
2004541400432530001000200020001800005225415412483274200020002000541541111001100004307311611538100010001000542542542542542
20045415101384830001000200020001800005225415412483274200020002000541541111001100000347311611538100010001000542542542542542
2004541400432530001000200020001800005225415412483274200020002000541541111001100000007311611538100010001000542542542542542
2004541400432530001000200020001800005225415412483274200020002000541541111001100000007311611538100010001000542542542542542
2004541400852530001000200020001800015225415412483274200020002000541541111001100000007311611538100010001000542542542542542

Test 2: Latency 1->2 roundtrip

Code:

  fcvtns w0, d0
  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 instruction (07)mmu table walk data (08)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)6061696b6d6emap 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)branch mispred nonspec (cb)cdcfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
3020413003897400000001300231194172540100101002000010000100200001000050062149791480103402130013013003813003812547631262463010020010000200002001000020000130038130078512020110099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003897400000001300231194172540100101002000010000100200001000050062149791480103400130013013003813007412547631262463010020010000200002001000020000130097130057112020110099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003897400000001300241194172540100101002000010000100200001000050062149791480103400130013013003813003812547631262463010020010000200002001000020000130038130104112020110099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003897400000001300241194172540100101002000010000100200001000050062149791480103400130013013003813003812547631262463028420010000200002001000020000130038130092112020110099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003897400000001300231194172540100101002000010001100200001000050062149791480103405130013313003813003812547631262463010020010000200002001006420000130038130086112020110099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003897400000001300231194172540100101002000010000100200001000050062149791480103400130013013003813003812547631262463010020010000200002001000020000130038130081512020110099100101001000010000100000000001131012162212952510000100001000010100130039130039130039130039130039
3020413003897400003001300231194172540100101002000010000100200001000050062149791480103400130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000000010131012162212952510000100001000010100130039130039130039130039130039
30204130038974000000013002311941725401001010020000100001002000010000500621497914801034001300130130038130038125476201262533010020010000200002001000020000130038130091112020110099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130074
3020413003997400000001300231194082540100101002000010000100200001000050062149791480103400130013013003813003812547631262463010020010000200002001000020000130038130104112020110099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003897400000001300231194202540100101032000010000100200001000050062149791480103400130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130039

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0038

retire uop (01)cycle (02)03mmu table walk instruction (07)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)60696d6emap 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 mispred nonspec (cb)cfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)ec? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
300241300399740000000001300231194172540010100102000010000102000010000506214979148000250130013130038130038125498312626830010201000020000201000020000130038130038112002110910100101000010001000000000127021622129525100000100001000010010130091130064130039130039130039
300241300389740000000001300231194172540010100102000010000102000010000506214979148000250130013130038130038125498312626830010201000020000201000020000130038130038112002110910100101000010001000000000127021622129525100000100001000010010130042130058130039130046130039
30024130038974000000000130023119421254001010010200001000010200001000050621497914800025013001313003813003812549831262683001020100002000020100002000013003813003811200211091010010100001000100880220004500185142724813119010004137100001000010010130044130039130050130039130046
300241300389740000000001300231194172540010100102000010000132046610000506214979148000251130013130359130038125498312648130010201000020476201000020000130038130038112002110910100101000010001000000000127021622129525100000100001000010010130372130068130039130042130039
300241300389740000000011300231194172540010100102000010000102000010000506214979148000250130013130038130038125498312626830010201000020000221000020000130038130038112002110910100101000010201000000900127025022129528100000100001000010010130040130039130040130043130039
300241300399760000000001300231194172540010100102000010000102000010000506214979148204450130013130038130038125498312626830010201000020000201000020000130038130038112002110910100101000010001000000000127021622129525100000100001000010010130068130047130039130039130039
300241300389740000000001300231194172540010100102000010000102000010000506214979148000250130013130038130038125498312626830010201000020000201000020482130038130038112002110910100101000010001000010000127021622129525100050100001000010010130053130039130039130039130039
300241300389740000001235201300231195542540010100102000010000102000010000506214979148000250130013130038130038125498312626830010221000020000201000020000130038130038112002110910100101000010001000000000127021632129528100000100001000010010130060130040130039130039130039
3002413003997400004000013002311941725400101001020000100001020466100005062149791480002501300131300381300381254993126268300102010000200002010000200001300381303741120021109101001010000100010000001714700127021622129525100000100001000010010130041130383130039130064130039
300241300389740100000001300231194182540010100102000010000102000010098506214979148000250130015130038130038125498912626830010201000020000201000020000130038130038112002110910100101000010201000000900127025022129525100000100001000010010130468130043130039130044130039

Test 3: throughput

Count: 8

Code:

  fcvtns w0, d8
  fcvtns w1, d8
  fcvtns w2, d8
  fcvtns w3, d8
  fcvtns w4, d8
  fcvtns w5, d8
  fcvtns w6, d8
  fcvtns w7, d8
  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)09l2 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)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)ld unit uop (a6)l1d cache writeback (a8)a9acc2branch 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
16020440041299000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000000111511701600400388000080000801004004240042400424004240042
16020440041300000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000000111511701600400388000080000801004004240042400424004240042
16020440041300000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000000111511701600400388000080000801004004240042400424004240042
16020440041299000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000000111511701600400388000080000801004004240042400424004240042
1602044020731400000008022524010480100160004100160020500144013204002240041400411997714199921601202001600322001600324004140041118020110099100801001000000000111511701600400388000080000801004004240042400424004240042
16020440041300000000074252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000000111511711600400388000080000801004004240042400424004240042
160204400413000000000259252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000001000111511701600400388000080000801004004240042400424004240042
160204400413000000012074252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000030111511701600400388018880000801004004240042400424004240201
16020440041300001000032252403788010016040010016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000000111511701600400388000080000801004004240042400424004240042
16020440041310000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000030111511701600400388000080000801004004240042400424004240042

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)60696d6emap stall dispatch (70)rob full (74)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)l1d cache writeback (a8)acc2cdcfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)eb? simd retires (ee)? int retires (ef)f5f6f7f8fd
160024410673092110000182818724173281062161358101614285014525440407194067340681202100582042716143420162228201617844076241220718002110910800101020123540530304205284094881399080000800104028440198400424004241401
1600244101031900022276010125725240010800101600001016000050144000004002240041400411999603200211600102016000020160000400414004111800211091080010100000050200216114003880000080000800104004240042400424004240042
1600244004129900000004225240010800101600001016000050144000004002240041400411999603200211600102016000020160000400414004111800211091080010100000050200216114003880000080000800104004240042400424004240042
1600244004129900000004225240010800101600001016000050144000004002240041400411999603200211600102016000020160000400414004111800211091080010100000050200116124003880000080000800104004240042400424004240042
1600244004130000000004225240010800101600001016000050144000004002240041400411999603200211600102016000020160000400414004111800211091080010100000050200116114003880000080000800104004240042400424004240042
16002440041300000000042252400108001016000010160000501440000040022400414004119996032002116001020160000201600004004140041118002110910800101000300502001161140038800001480000800104004240042400424004240042
1600244004130000000004225240010800101600001016000050144000004002240041400411999603200211600102016000020160000400414004111800211091080010100000050200116114003880000080000800104004240042400424004240042
1600254004130000000004225240010800101600001016000050144000004002240041400411999603200211600102016000020160000400414004111800211091080010100100050200116114003880000080000800104004240042400424004240042
1600244004130000000004225240010800101600001016000050144000004002240041400411999603200211600102016000020160000400414004111800211091080010100000050200116114003880000080000800104004240042400424004240042
1600244004130000000004225240010800101600001016000050144000004002240041400411999603200211600102016000020160000400414004111800211091080010100000050200116134003880000080000800104004240042400424004240042