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

FCVTAU (scalar, D to W)

Test 1: uops

Code:

  fcvtau 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
2004541404325300010002000200018000052254154124832742000200020005415411110011000007341611538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000152254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000152254154124832742000200020005415411110011000007311611538100010001000542542542542542
20045414154325300010002000200018000152254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000152254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000152254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000152254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000052254154124832742000200020005415411110011000007311611538100010001000542542542542542
2004541404325300010002000200018000152254154124832742000200020005415411110011000007311611538100010001000542542542542542

Test 2: Latency 1->2 roundtrip

Code:

  fcvtau 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)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)9d9fld unit uop (a6)l1d cache writeback (a8)abacl1d tlb miss nonspec (c1)c2branch mispred nonspec (cb)cfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30204130043120100000013002311941725401001010020000100001002000010000500621497914801034013001301300381300381254763126246301002001000020000200100002000013003813003811202011009910010100100000100100003700000131012161212952510000100001000010100130039130039130039130039130039
302041300411008000240013002311941725401001010020000100001002000010000500621497914801034013001301300381300381254763126246301002001000020000200100002000013003813003811202011009910010100100000100100000210000131012162212952710000100001000010100130039130039130039130039130039
3020413003810080000011300231194172540106101002000010000100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000010010000000000131012162212958010000100001000010100130039130039130039130039130039
30204130038100800000013002311941725401001010020000100001002000010000500621497914801034013001301300381300381254763126246301002001000020000200100002000013003813003811202011009910010100100000100100002008101133512162212952510000100001000010100130039130039130039130039130039
3020413003810080000001300231194662540100101002000010001100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000010010000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003810080009001300231194172540100101002000010000100200001000050062149791480103401300130130038130038125476312624630100200100002000020010000200001300821300451120201100991001010010000010010000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003810080000001300231194712540100101002000010000100200001000050062149791480103401300130130038130038125479312624630100200100002000020010000200001300381300381120201100991001010010000010010000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003810080000001300231194192540130101002000010000100200001000050062149791480103411300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000010010000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003810080000001300231194172540100101002000010000100200001000050062149791480103401300130130038130038125498312624730100200100002000020010000200001300381300411120201100991001010010000010010000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003810080000001300231194173540100101002000010000100200001000050062149791480103411300130130039130038125476312624630100200100002000020010000200001300381300381120201100991001010010000010010000000000131012162212952510000100001000010100130039130039130039130039130039

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0038

retire uop (01)cycle (02)030918191e3f4f51schedule 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)9fld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9acc2branch mispred nonspec (cb)cdcfd2d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30024130038100800001300231194172540010100102000010000102000010000506214979148000250130013130038130038125498312626830010201000020000201000020000130038130038112002110910100101000010100000000000127003165412952510000100001000010010130039130039130039130039130039
30024130038100800001300231194172540010100102000010000102000010000506214979148000250130013130041130038125498312626830010201000020000201000020000130038130038112002110910100101000010100010000000127004164412952510000100001000010010130039130039130039130039130039
30024130038100800001300231194172540010100102000010000102000010000506214979148000250130013130038130038125498312626830010201000020000201000020000130038130038112002110910100101000010100000000000127004166512952510000100001000010010130039130039130069130039130039
300241300389740000130023119417254001010010200001000010200001000050621497914800025013001313003813003812549819126324300102010000200002010000200001300381300381120021109101001010000101000000033000127005164412952510000100001000010010130039130039130039130039130039
3002413003897400001300231194172540010100102000010000102000010000506214979148000250130013130038130038125498312626830010201000020000201000020000130038130038112002110910100101000010100000000000127004165412952510000100001000010010130039130039130075130081130039
3002413003897400001300231194172540010100132000010000102000010000506214979148000250130013130038130038125498312626830010201000020000201000020000130038130038112002110910100101000010100000000000127005165512952510000100001000010010130039130039130039130039130039
3002413003897400001300231194172540010100102000010000102000010000506214979148000250130013130038130038125498312626830177201000020000201000020000130038130038112002110910100101000010100000100000127004165712960710000100001000010010130039130039130039130039130039
3002413003897400001300231194172540010100102000010000102000010000506215075148089260130013130038130038125498312626830010201000020000201000020000130038130038112002110910100101000010100120103000127004165512952510000100001000010010130039130039130039130039130039
30024130038974000961300231194182540010100102000010000102000010000506214979148000250130013130038130038125498312626830010201000020000201000020000130038130038112002110910100101000010100000000000127004164512952510000100001000010010130039130039130039130039130039
30024130038974000013002311941725400101001020000100001020000100005062149791480002501300131300381300381254983126268300102010000200002010000200001300381300761120021109101001010000101000000000001270051642212955910000100001000010010130041130039130039130039130039

Test 3: throughput

Count: 8

Code:

  fcvtau w0, d8
  fcvtau w1, d8
  fcvtau w2, d8
  fcvtau w3, d8
  fcvtau w4, d8
  fcvtau w5, d8
  fcvtau w6, d8
  fcvtau 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)0318191e1f3f51schedule 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)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
16020440053311001203225240104801001600041001600205001440132140022400414004119977619992160120200160032200160032400414004111802011009910080100100000111511701600400388000080000801004004240042400424004240042
1602044004131000003225240104801001600041001600205001440132140022400414004119977619992160120200160032200160032400414004111802011009910080100100000111511701600400388000080000801004004240042400424004240042
1602044004131000007425240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100030111511701600400388000080000801004004240042400424004240042
1602044004131000004625240104801001600041001600205001440132140022400414004119977619992160120200160032200160032400414004111802011009910080100100000111511701600400388000080000801004004240042400424004240042
1602044004131100003225240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100000111511701600400388000080000801004004240042400424004240042
1602044004131100003225240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100000111511701610400388000080000801004004240042400424004240042
1602044004131000003225240104801001600041001600205001440132140022400414004119977619992160120200160032200160032400414004111802011009910080100100000111511701600400388000080000801004004240042400424004240042
1602044004131000003225240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100000111511701600400388000080000801004004240042400654006340053
1602044005131000003225240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100000111511701600400388000080000801004004240042400424004240042
1602044004131000003225240104801001600041001600205001440132140022400414004119977619992160120200160032200160032400414004111802011009910080100100000111511701600400388000080000801004004240042400424004240042

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)5f60696b6d6emap 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)l1d cache writeback (a8)a9accfd0d2l1i cache miss demand (d3)d5map dispatch bubble (d6)d9ddfetch restart (de)e0? int output thing (e9)ea? simd retires (ee)? int retires (ef)f5f6f7f8fd
16002440055310000000022025240010800101600001016000050144000001400220400414004119996320021160010201600002016000040041400411180021109108001010000050200005160444003880000080000800104004240042400424004240042
16002440041310000000042225240010800101600001016000050144000001400220400414004119996320021160010201600002016000040041400411180021109108001010000050200005160554003880000080000800104005340042400424004240042
1600244004131000000004225240010800101600001016000050144000001400220400414004119996320021160010201600002016000040041400411180021109108001010000050200003160554003880000080000800104004240042400424004240042
1600244004131100000004225240010800101600001016000050144000001400220400414004119996320021160010201600002016000040041400411180021109108001010010050200002160334003880000080000800104004240042400424004240042
1600244004131000000004225240010800101600001016000050144000000400220400414004119996320021160010201600002016000040041400411180021109108001010000050200005160444003880000080000800104004240042400424004240042
16002440041310000000070725240010800101600001016000050144000001400220400414004119996320021160010201600002016000040041400411180021109108001010000050200005160554003880000080000800104004240042400424004240042
1600244004131000000004225240010800101600001016000050144000001400220400414004119996320021160010201600002016000040041400411180021109108001010000350200004160244003880000080000800104004240042400424004240042
1600244004131000000004225240010800101600001016000050144000001400220400414004119996320021160010201600002016000040041400411180021109108001010000350200005160444003880000080000800104004240042400424004240042
1600244004131100000004225240010800101600001016000050144000001400220400414004119996320021160010201600002016000040041400411180021109108001010020050200004160444003880000080000800104004240042400424004240042
1600244004131100000008425240010800101600001016000050144000001400220400414004119996320021160010201600002016000040041400411180021109108001010000050200004160344003880000080000800104004240042400424004240042