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 X)

Test 1: uops

Code:

  fcvtns x0, 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)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
200454140432530001000200020001800005225415412483274200020002000541541111001100007331633538100010001000542542542542542
200454140432530001000200020001800015225415412483274200020002000541541111001100007331623538100010001000542542542542542
2004541418432530001000200020001800005225415412483274200020002000541541111001100007331633538100010001000542542542542542
200454140432530001000200020001800005225415412483274200020002000541541111001100007331633538100010001000542542542542542
200454140432530001000200020001800015225415412483274200020002000541541111001100007331633538100010001000542542542542542
200454149432530001000200020001800015225415412483274200020002000541541111001100007331633538100010001000542542542542542
200454140432530001000200020001800015225415412483274200020002000541541111001100007331633538100010001000542542542542542
200454140432530001000200020001800015225415412483274200020002000541541111001100007331633538100010001000542542542542542
200454140432530001000200020001800015225415412483274200020002000541541111001100007331633538100010001000542542542542542
200454140432530001000200020001800015225415412483274200020002000541541111001100007331633538100010001000542542542542542

Test 2: Latency 1->2 roundtrip

Code:

  fcvtns x0, 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)0318191e1f3f4f5051schedule 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)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
3020413003897400001300231194170254010910100200001000010020000100005006214979148010341130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000090000131013162212953410000100001000010100130039130039130039130039130039
30204130040974000013002311941702540100101002000010000100200001000050062149791480103411300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100001000000210000131012162212952510000100001000010100130039130039130039130039130039
3020413003897400001300231194170254010010100200001000010020000100005006214979148010341130013013003813003812547631262463010020010000200002001000020000130038130042112020210099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130039
30204130199974000013002311941702540100101002000010000100200001000050062149791480103411300130130038130038125476312624930100200100002000020010000200001300381300391120201100991001010010000100001000011085292000135022162212960010000100001000010100130040130039130039130039130039
30204130044974003301300231194170254010010100200001000010020000100005006214979148010341130013013003813003912547631262463010020010000200002001000020000130038130042112020110099100101001000010000100007000000131012162212952510000100001000010100130039130039130039130039130039
30204130038974005752813002311941702540100101002000010000100200001000050062149791480103411300130130038130038125476312624730100200100002000020010000200001300381300381120201100991001010010000100001000000930000131012162212952510000100001000010100130039130039130039130039130039
3020413005397400001300231194170254010010100200001000010020000100005006214979148010341130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000000000131012172212952510000100001000010100130039130039130039130039130039
30204130038974005401300231194170254010010100200001000010020000100005006214979148010341130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003897400001300231194170254010010100200001000010020000100005006214979148026201130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130039
3020413003897400001300231194170254010010100200001000010020000100005006214979148010341130013013003813003812547631262463010020010000200002001000020000130038130038112020110099100101001000010000100000000000131012162212952510000100001000010100130039130039130039130039130039

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0038

retire uop (01)cycle (02)0309l2 tlb miss data (0b)18191e3a3f4f51schedule 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)a9acc3branch 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
3002413003810080000001300231194172540010100102000010000102000010000506214979148000250130013130038130038125499312626830010201000020000201000020000130038130038112002110910100101000010001000000000012701161112952510000100001000010010130039130039130039130039130039
3002413003810080000001300231194172540010100102000010000102000010000506214979148000251130013130038130096125498312626830010201000020000201000020000130038130038112002110910100101000010001000000000012701161112952510000100001000010010130039130039130039130039130039
3002413003810080000001300231194172540010100102000010000102000010000506214979148000251130015130038130038125499312626830010201000020000201000020000130201130040112002110910100101000010001000000300012701161112952510000100001000010010130039130039130039130039130039
3002413003810080000001300231194172540010100102000010000102000010000506214979148000250130013130038130038125506312626830010201000020000201000020000130038130038212002110910100101000010001000000000012701161112952510000100001000010010130039130039130039130039130039
3002413003810080000001300231194172540010100102000010000102000010000506214979148000251130013130038130098125498312626830010201000020000201000020000130038130038112002110910100101000010001000000000012702161512952510000100001000010010130039130039130039130039130039
3002413003810080000001300251194172540010100102000010000102000010000506214979148000250130013130104130058125498312626830010201000020000201000020000130038130038112002110910100101000010001000000000012701161112952510000100001000010010130039130039130039130039130039
3002413003810080002001300231194172540010100102000010000102000010000506214979148000250130013130038130112125498312626830010201000020000201000020000130038130038112002110910100101000010001000000000012701161112952510000100001000010010130039130039130039130039130039
3002413003810080000001300231194172540010100102000010000102000010000506214979148000251130013130099130045125498312626830010201000020000201000020000130069130038112002110910100101000010001000000000012701161112952510000100001000010010130039130039130039130039130039
300241300381008000000130023119417254001010010200001000010200001000050621497914800025113001313003813013312549831262683001020100002000020100002000013003813003811200211091010010100001000100000001300770012701161112952510000100001000010010130039130039130039130039130039
3002413003810080000001300231194172540010100102000010000102000010000506214979148000250130018130038130110125498312626830010201000020000201000020000130038130038112002110910100101000010001000000000012701161112952810000100001000010010130039130039130039130039130039

Test 3: throughput

Count: 8

Code:

  fcvtns x0, d8
  fcvtns x1, d8
  fcvtns x2, d8
  fcvtns x3, d8
  fcvtns x4, d8
  fcvtns x5, d8
  fcvtns x6, d8
  fcvtns x7, 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)1e3f51schedule 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)5e60696b6d6emap 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)ddfetch restart (de)dfe0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1602044004131000322524010480100160004100160020500144013200400220400414004119977619992160120200160032200160032400414004111802011009910080100100001115119316002400388000080000801004004240042400424004240042
1602044004131000322524010480100160004100160020500144013200400220400414004119977619992160120200160032200160032400414004111802011009910080100100031115119016002400388000080000801004004240042400424004240042
1602044004131100322524010480100160004100160020500144013201400220400414004119977619992160120200160032200160032400414004111802011009910080100100001115119016002400388000080000801004004240042400424004240042
1602044004132100322524010480100160004100160020500144013201400220400414004119977619992160120200160032200160032400414004111802011009910080100100001115119016002400388000080000801004004240042400424004240042
1602044004131100322524010480100160004100160020500144013201400220400414004119977619992160120200160032200160032400414004111802011009910080100100001115119016012401268000080000801004004240042400424004240042
16020440041310015322524010480100160004100160020500144013200400220400414004119977619992160120200160032200160032400414004111802011009910080100100001115119016002400388000080000801004004240042400424004240042
1602044004131000322524010480100160004100160020500144013200400220400414004119977619992160120200160032200160032400414004111802011009910080100100001115119016012400388000080000801004004240042400424004240042
1602044004131000322524010480100160004100160020500144013201400223400414004119977619992160120200160032200160032400414004111802011009910080100100001115119016002400388000080000801004004240042400424004240042
1602044004131000322524010480100160004100160020500144013201400220400414004119977619992160120200160032200160032400414004111802011009910080100100001115119016002400388000080000801004004240042400424004240042
1602044004131100322524010480100160004100160020500144013201400220400414004119977619992160120200160032200160032400414004111802011009910080100100001115119016002400388000080000801004004240129400424004240042

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)03l2 tlb miss instruction (0a)l2 tlb miss data (0b)0f18191e1f3f51schedule 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 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)d9ddfetch restart (de)e0? int output thing (e9)ea? simd retires (ee)? int retires (ef)f5f6f7f8fd
160024400423100000000707252400108001016000010160000501440000040022040041400411999632002116001020160000201600004004140041118002110910800101000000000005020716057400388000012180000800104004240042400424004240042
1600244004132200000001062524001080010160000101600005014400001400220400414004119996320021160010201600002016000040041400411180021109108001010000000000050205160554003880000080000800104004240042400424004240042
160024400413100000000762524001080010160000101600005014400001400220400414004119996320021160010201600002016000040041400411180021109108001010000000000050203160534003880000080000800104004240042400424004240042
160024400413220000000822524001080010160000101600005014400000400220400414004119996320021160010201600002016000040041400411180022109108001010000000000050204160644003880000080000800104004240042400424004240042
1600244004131000000002782524001080010160000101600005014400001400220400414004119996320021160010201600002016000040041400411180021109108001010000000000050203160534003880000080000800104004240042400424004240042
16002440041311000000062525240010800101600001016000050144000014002204004140041199967420021160010201600002016000040041400411180021109108001010000000000050203160354003880000080000800104004240042400424004240042
160024400413100000000762524001080010160000101600005014400001400220400414004119996320021160010201600002016000040041400411180021109108001010000000000050203160544003880000080000800104004240042400424004240042
16002440041311000000010652524001080010160000101600005014400001400220400414004119996320021160010201600002016000040041400411180021109108001010000000000050204160554003880000080000800104004240042401274004240042
160024400413100000000762524001080010160000101600005014400001400220400414004119996320021160010201600002016000040041400411180021109108001010000000000050205160354003880000080000800104004240042400424004240042
160024400413100000000822524001080010160000101600005014400001400220400414004119996320021160010201600002016000040041400411180021109108001010000000000050206160454003880000080000800104004240042400424004240042