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

FCVTAS (scalar, D to W)

Test 1: uops

Code:

  fcvtas 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)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
2004541404325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000037311611538100010001000542542542542542
2004541408525300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000407311611538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542

Test 2: Latency 1->2 roundtrip

Code:

  fcvtas 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)03l2 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)ld unit uop (a6)l1d cache writeback (a8)a9accdcfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
302041300389740000013002311941725401001010020000100001002000010000500621497914801034113001301300381300381255343126246301002001000020000200100002000013003813003811202011009910010100100001000100000000131012162212959910007100001000010100130039130067130039130039130039
3020413003897400063013002311941725401001010020000100001002000010000500621497914801034013001301300381300381255103126246301002001000020000200100002000013003813003811202011009910010100100001000100000000131012162212952510000100001000010100130039130039130039130039130039
302041300389740000013002311946025401001010020000100001002000010000500621497914801034113001301300381300381255293126246302722001000020000200100002000013003813003811202011009910010100100001000100000060131012162212952510000100001000010100130039130039130039130039130039
302041300389740000013002311941725401001010020000100001002000010000500621497914801034013001301300381300381255233126246301002001000020000200100002000013003813003811202011009910010100100001000100000001131012162212952510000100001000010100130039130039130039130039130039
302041300389740000013002311941725401001010020000100001002000010000500621497914801034113001301300381300381254763126246301002001000020000200100002000013003813003811202011009910010100100001000100000000131013162212959510000100001000010100130039130039130039130039130041
302041300389740000013002311941736401001010020000100011002000010000500621502714801034113001301300381300381255703126246301002001000020000200100002000013003813003811202011009910010100100001000100000000131012162212952510000100001000010100130039130039130039130039130039
302041300389740000013002611941725401001010020000100001002000010000500621497914801034113001301300391300381255263126246301002001000020000200100002000013003813003811202011009910010100100001000100000000131012162212957010000100001000010100130039130039130040130039130039
302041300389750000013002311941725401001010020000100001002000010000500621497914801034113001301300381300381255383126246301002001000020000200100002000013003813003911202011009910010100100001000100001000131012162212952510000100001000010100130039130039130039130039130039
302041300389730000013002311941725401001010020000100001002000010000500621497914801034013001301300381300381255253126246301002001000020000200100002000013003813003811202011009910010100100001000100000000131011162212952510000100001000010100130039130039130039130039130039
302041300389740000013002311942225401001010020000100001002000010000500621497914801034013001301300381300411254833126246301002001000020000200100002000013003813003811202011009910010100100001000100000000131012162212952510001100001000010100130039130039130039130039130039

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0038

retire uop (01)cycle (02)03mmu table walk instruction (07)09l2 tlb miss data (0b)18191e3f4f51schedule 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)91inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d tlb access (a0)ld unit uop (a6)l1d cache writeback (a8)a9acbranch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30024130038974000000130023119417254001010010200001000010200001000050621497914800025113001313003813003812549831262683001020100002000020100002000013003813003811200211090101001010000100100000000012703162212952510000100001000010010130039130039130039130039130039
300241300389740000024130023119466254001010010200001000010200001000050621497914800025113001513003813004012549831262683001020100002012120100002000013004013007311200211090101001010000100100000060012702162212952810000100001000010010130039130039130039130039130140
30024130042974100000130023119417254001010010200001000010201201000050621497914800025013001313003913003812549831262683001020100002000020100002000013003813003811200211090101001010000100100000000012702162212952510000100001000010010130039130039130039130039130039
30024130038974000000130023119417254001010010200001000010200001000050621497914800025013001313003813003812549831262683001020100002000020100002000013003813003811200211090101001010000100100000000012702162212952510000100001000010010130041130040130039130039130039
30024130038974000000130023119417254001010010200001000010200001000050621497914800025013001313003813003812549831262683001020100002000020100002000013003813003811200211090101001010000100100000000012703162212952510000100001000010010130039130039130039130039130039
30024130038974000000130023119417254001010010200001000010200001000050621497914800025113001313003813003812549831262683001020100002000020100002000013004113011311200211090101001010000100100000000012702162212952510000100001000010010130039130039130039130039130039
30024130038974000000130023119417254001010010200001000010200001000050621497914800025113001313003813003812549831262683001020100002000020100002000013003813003811200211090101001010000100100000000012703162312952510000100001000010010130039130039130039130039130039
30024130038974000000130023119417254001010010200001000010200001000050621497914800025013001313003813003812549831262683001020100002000020100002000013003813003811200211090101001010000100100004030012702162212952510004100001000010010130039130039130039130039130039
30024130038974000100130023119417254001010010200001000010200001000050621497914800025013001313003813003812549831262683001020100002000020100002000013003813006211200221090101001010000100100000000012702162212952510000100001000010010130039130039130039130039130039
30024130038974000000130023119417254001010010200001000010200001000050621694714800025013001313003813003812549831262713001020100002000020100002000013003813012011200211090101001010000100100000000012702162212952510000100001000010010130039130039130039130039130039

Test 3: throughput

Count: 8

Code:

  fcvtas w0, d8
  fcvtas w1, d8
  fcvtas w2, d8
  fcvtas w3, d8
  fcvtas w4, d8
  fcvtas w5, d8
  fcvtas w6, d8
  fcvtas 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 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)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)acc2branch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)ea? simd retires (ee)? int retires (ef)f5f6f7f8fd
160204400533100000000032252401048010016000410016002050014401321400224004140041199776199921601202001600322001600324004140041118020110099100801001000000001115117016004003880000080000801004004240042400424004240042
160204400413100000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000001115117016004003880000080000801004004240042400424004240042
160204400413100000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000001115117016004003880000080000801004004240042400424004240042
160204400413110000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000001115117016004003880000080000801004012140121400424004240042
160204400413100000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000001115117016004003880000080000801004004240042400424004240042
160204400413100000000032252401048010016000410216002050014401320400704004140041199776199921601202001600322001600324004140041118020110099100801001000000001115117016004003880000080000801004004240042400424004240042
160204400413100000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000001115117016004003880000080000801004004240042400424004240042
160204400413100000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000000001115117016004003880000080000801004004240042400424004240042
160204400413100000000032252401048010016000410016002050014401320400224004140041199776199921601202021600322001600324004140041118020110099100801001000000001115117016004003880000080000801004012440042400424004240042
16020440041310000000006972524010480100160004100160020500144013204002240041400411997761999216012020016003220016003240041400411180201100991008010010000021001115117016004003880000080000801004004240042400424004240042

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)1e1f3f51schedule 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)a9acc2cfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
160024400552990007072524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100000503011611400388000080000800104004240042400424004240042
16002440041299000422524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010101000503011611400388000080000800104004240042400424004240042
160024400413110004225240281801041600001016000050144000004002240041401191999623200211600102016021420160000400414012311800211091080010101402503032511400388000080000800104004240042400424004240042
1600244004131302191322322524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100000503011611400388000080000800104004240042400424004240042
16002440041300000422524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100030503011611400388000080000800104004240042400424004240042
16002440041300000422524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100000503111611400388000080000800104004240042400424004240364
160024400413000330422524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100000503011611400388000080000800104004240042400424004240042
16002440041300000422524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100000503111611400388000080000800104004240042400424004240130
160024400413000001372524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100000503011611400388000080000800104004240042400424004240042
16002440041300000422524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100000503011611400388000080000800104012840042400424004240042