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

FCVTZU (scalar, fixed-point, S to X)

Test 1: uops

Code:

  fcvtzu x0, s0, #3
  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)033f51schedule 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
200454144325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
200454144325300010002000200018000152254154124832742000200020005415411110011000007311611538100010001000542542542542542
200454144325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
200454144325300010002000200018000052254154124832742000200020005415411110011000037311611538100010001000542542542542542
200454144325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
200454144325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
200454144325300010002000200018000052254154124832742000200020005415411110011000207311611538100010001000542542542542542
200454144325300010002000200018000052254154124832742000200020005415411110011000107311611538100010001000542542542542542
200454144325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
200454144325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542

Test 2: Latency 1->2 roundtrip

Code:

  fcvtzu x0, s0, #3
  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)0309l2 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)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 miss (a1)ld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9acbranch cond mispred nonspec (c5)c9branch mispred nonspec (cb)cdcfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)ec? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30204130038974000000130023119456254010010100200001000010020000100005006214979148010341130013130038130038125476312624630100200100002000020010000201291300381300381120201100991001010010000100010000000000001310111622129525100000100001000010100130039130039130094130059130039
30204130038974000000130023119417254010010100200001000010020000100005006214979148010340130013130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000001310121622129525100000100001000010100130039130039130112130042130039
30204130038974000000130023119418254010010116200001000010020000100005006214979148010340130013130038130042125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000001310121622129525100000100001000010100130039130039130044130090130039
30204130038974000000130023119422254010010100200101000010020000100005006214979148010341130013130038130038125476312624730100200100002000020010000200001300381300381120201100991001010010000100010000000000001310121622129528100000100001000010100130039130039130090130053130039
30204130038974000000130023119417254010010100200001000010020000100005006214979148010340130013130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000001310121622129525100000100001000010100130039130039130097130042130039
30204130038974000000130023119417254010010100200001000010020000100005006214979148010341130013130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000001310111622129525100000100001000010100130039130039130039130113130039
30204130038973000000130023119417254010010100200001000010020000100005006214979148010341130013130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000001310121622129525100000100001000010100130039130039130079130040130039
302041301299740000270130023119417254010010100200001000010020000100005006214979148010341130016130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000101310121622129525100000100001000010100130039130039130114130047130039
30204130038974000000130023119471254010010100200001000010020000100005006214979148010341130013130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000001310121622129548100000100001000010100130039130092130066130041130039
30204130038974000000130023119417254010010100200001000010020000100005006214979148010340130013130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000001310121622129525100000100001000010100130039130039130102130040130039

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0038

retire uop (01)cycle (02)03mmu table walk data (08)09l2 tlb miss data (0b)191e1f3f4f51schedule 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)st unit uop (a7)l1d cache writeback (a8)a9acc2branch cond mispred nonspec (c5)branch 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
3002413003897400000013002311941725400101001020000100001020000100005062150271480047201300131300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000012702161112984810004100001000010010130128130039130464130039130039
3002413003897411000013002311941725400101001020000100001020000100005062149791480002501300131300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000012701161112952810000100001000010010130039130039130039130039130039
3002413003897400000013002311941725400101001020000100001020000100005062149791480002501300131300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000012701161112952510000100001000010010130039130039130039130039130039
3002413003897400000013002311941725400101001020000100001020000100005062149791480002501300131300381300381254983126268300102010000200002010000200001300411300391120021109101001010000100010000000000012701161112952510000100001000010010130039130039130039130039130039
3002413003897400000013002311941725400101001020000100001020000100005062149791480002501300131300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000012701161112952510000100001000010010130039130039130039130039130039
3002413003897400000013002511941725400101001020000100001020000100005062149791480002501300131300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000012701161112952510000100001000010010130039130039130039130039130039
3002413003897400000013002311941725400101001020000100001020000100005062149791480002501300131300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000012701162112952510000100001000010010130039130039130039130039130039
3002413003897300000013002311941725400101001020000100001020000100005062149791480014001300131300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000012701161112952510000100001000010010130039130039130039130039130039
3002413003897400000013002311941725400101001020000100001020000100005062149791480002501300131300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000012701162112952510000100001000010010130045130040130376130039130039
3002413003897400000013002311941725400101001020000100001020000100005062149791480002501300131300381300381254983126268300102010000200002010000200001300411300381120021109101001010000100410004010300012701161112952510000100001000010010130039130039130040130039130039

Test 3: throughput

Count: 8

Code:

  fcvtzu x0, s8, #3
  fcvtzu x1, s8, #3
  fcvtzu x2, s8, #3
  fcvtzu x3, s8, #3
  fcvtzu x4, s8, #3
  fcvtzu x5, s8, #3
  fcvtzu x6, s8, #3
  fcvtzu x7, s8, #3
  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)031e1f3f51schedule 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)60696b6d6emap 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)cdcfd2d5map dispatch bubble (d6)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1602044007730000322524010480100160004100160020500144013204002204004140041199776199921601202001600322001600324004140041118020110099100801001000011151170016400388000080000801004004240042400424004240042
16020440041300009122524010480100160004100160020500144013204002204004140041199776199921601202001600322001600324004140041118020110099100801001000011151170016400388000080000801004004240042400424004240042
16020440041300603225240104801001600041001600205001440132040022040041400411997712200351601202001600322001600324004140041118020110099100801001000011151170016400388000080000801004004240042400424004240042
1602044004130000322524010480100160004100160020500144013204002204004140041199776199921601202001600322001600324004140041118020110099100801001000011151170016400388000080000801004004240042400424004240042
1602044004130000322524010480100160004100160020500144013204002204004140041199776199921601202001600322001600324004140041118020110099100801001000011151170016400388000080000801004004240042400424004240042
1602044004130000322524010480100160004100160020500144013204002204004140041199776199921601202001600322001600324004140041118020110099100801001000011151170016400388000080000801004004240042400424004240042
1602044004129900322524010480100160004100160020500144013204002204004140041199776199921601202001600322001600324004140041118020110099100801001000011151170016400388000080000801004004240042400424004240042
1602044004130090322524010480100160004100160020500144013204002204004140041199776199921601202001600322001600324004140041118020110099100801001000011151170016400388000080000801004004240042400424004240042
1602044004129900322524010480100160004100160020500144013204002204004140041199776199921601202001600322001600324004140041118020110099100801001000011151170016400388000080000801004004240042400424004240042
1602044004129900322524010480100160004100160020500144013204002204004140041199776199921601202001600322001600324004140041118020110099100801001000011151170016400388000080000801004004240042400424004240042

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)031e3f51schedule 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)ld unit uop (a6)l1d cache writeback (a8)accfd2l1i cache miss demand (d3)d5map dispatch bubble (d6)d9dbddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1600244005529902372524001080010160000101600005014400001400224004140041199963200211600102016000020160000400414004111800211091080010100000502000141603515400388000080000800104004240042400424004240042
160024400413000422524026680010160000101600005014400001400224004140041199963200211600102016000020160000400414004111800211091080010100000502000616001615400388000080000800104004240042400424004240042
160024400413000422524001080010160000101600005014400001400224004140041199963200211600102016000020160000400414004111800211091080010100000502000161600165400388000080000800104004240042400424004240042
1600244004130004225240010800101600001016000050144000014002240041400411999632002116001020160000201600004004140041118002110910800101000005020001616001615400388000080000800104004240042400424004240042
1600244004130004225240010800101600001016000050144000014002240041400411999632002116001020160000201600004004140041118002110910800101000035020001616001615400388000080000800104004240042400424004240042
160024400412999842524001080010160000101600005014400001400224004140041199963200211600102016000020160000400414004111800211091080010100003502000616001615400388000080000800104004240042400424004240042
1600244004130012654924031480010160000101600005014436141400224012240041199963200211600102016020820160000402044004111800211091080010100010502000616001616400388000080000800104004240042400424004240042
160024400413000422524001080010160000101600005014400001400224004140041199963200211600102016000020160000400414004111800211091080010100010502000161600515400388000080000800104004240042400424004240042
1600244004130005172524001080010160000101600005014400001400224004140041199963200211600102016000020160000400414004111800211091080010100000502000161600515400388000080000800104004240042400424004240042
160024400413001242252400108001016000010160000501440000140281400414004120092320021160010201600002016000040041400411180021109108001010000050200061600615400388000080000800104004240042400424004240042