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

SCVTF (scalar, fixed-point, H from X)

Test 1: uops

Code:

  scvtf h0, x0, #3
  mov x0, 1
  mov x1, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 2.000

Issues: 2.000

Integer unit issues: 0.000

Load/store unit issues: 1.000

SIMD/FP unit issues: 1.000

retire uop (01)cycle (02)031e3f4f51schedule uop (52)schedule simd uop (54)schedule ldst uop (55)dispatch simd uop (57)dispatch ldst uop (58)simd uops in schedulers (5a)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map ldst uop (7d)map simd uop (7e)map ldst uop inputs (80)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst simd alu (9a)ld unit uop (a6)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)f5f6f7f8fd
2004376303610252000100010001000100014075228201357376376723109200010001000100010003763761110011000100010733162237310001000377377377377377
2004376303610252000100010001000100014075228200357376376723109200010001000100010003763761110011000100000732162237310001000377377377377377
2004376303610252000100010001000100014075228200357376376723109200010001000100010003763761110011000100000732162237310001000377377377377377
2004376303610252000100010001000100014075228200357376376723109200010001000100010003763761110011000100000732162237310001000377377377377377
2004376303610252000100010001000100014075228200357376376723109200010001000100010003763761110011000100000732162237310001000377379377377377
2004376203650252000100010001000100014075229110357376376723109200010001000100010003763761110011000100000732162237310001000377377377377377
2004376303610252000100010001000100014075228200357376376723109200010001000100010003763771110011000100000732162237310001000377379377377377
2004376303610252000100010001000100014075228200357376376723109200010001000100010003763761110011000100000732162237410001000377377377380379
2004376303610252000100010001000100014075228200357376376723109200010001000100010003763761110011000100020732162237310001000377377377377382
2004376303610252000100010001000100014075228200357376376723109200010001000100010003763761110011000100000732162237310001000377378377377384

Test 2: Latency 1->2 roundtrip

Code:

  scvtf h0, x0, #3
  fmov x0, d0
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 13.0032

retire uop (01)cycle (02)03mmu table walk data (08)l2 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)l1d tlb miss (a1)ld unit uop (a6)l1d cache writeback (a8)a9acbranch cond mispred nonspec (c5)cdcfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
302041300329740000001300171196072540100101002000010000100200001004950062144971480270911300130130032130033125466312624030429204100002000020010000200001300321300321120201100991001010010000100001000000300133012162212952410000100001000010100130033130033130036130033130033
30204131899994010100130017119556112401791011720003100001242000010000500621688214802709013001301311091303491254669126556301002001000020000200100002000013003213003211202011009910010100100001002210000001679300136612672312952310027100001000010100130033130128130033130033130033
302041300329740000001300171194112540100101002000010000100200001000050062166321480795701300130130365130033125466312624030100212100002048820010000200001300321300321120201100991001010010000100101000000600131012162212959910000100001000010100130582130033130033130033130033
3020413003297400101201301911194084740100101002000010002100200001000050062170141480270901300130130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100001000010300131012162312951910000100001000010100130033130033130132130033130036
302041305749740070001300171194532540100101002000010000100200001000050062147851480270901300150130035130033125466312624030100200100002000020010000200001300321300351120201100991001010010000100001000000000133512163212958310000100001000010100130033130033130033130033130033
30204130032974000014401300171194082540100101002000010000100200001000050062144971480270901300130130032130032125466312624330100200100002000020010000200001300341300321120201100991001010010000100041000022000131012162212952010000100001000010100130033130033130034130033130033
30204130034974000027013001811940810840100101002000310002100200001000050062144971480305101300140130032130116125466312624030100200100002000020010000200001300321300331120201100991001010010000100001000010000131012162312959910030100001000010100130033130122130033130130130033
30204130032985112621201300171194082540100101002000010000100200001000050062144971480270911300150130032130032125466312624030100200100002000020010000200001300331300321120201100991001010010000100001000010300131012162212952110000100001000010100130033130033130034130033130033
302041300329740000001300181194092540100101002000010000100200001000050062146411480293111300130130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100001000010300131012162212951910000100001000010100130033130033130034130034130033
3020413003297400002101300171194082540100101002000010000100200001000050062144971480270911300130130035130034125466312624030100200100002000020010000200001300321300321120201100991001010010000100001000010000131013172212951910000100001000010100130037130034130033130034130033

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0032

retire uop (01)cycle (02)03mmu table walk data (08)l2 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)9fld unit uop (a6)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30024130034975000012013001711940847400101001020003100001020000100005062144971480075611300130130032130032125491312626230010201000020000201000020000130032130032112002110910100101000010100000312701171112951910001100001000010010130125130300130033130124130036
30024130033975010012013001711940825400101001020000100001020000100005062145451480052811300130130032130033125489312626230010201000020000201000020000130033130035112002110910100101000010100000312701161112951910000100001000010010130033130033130033130033130033
30024130032974000012013001711940825400101001020003100001020113100495062144971480052811300130130112130033125492312626230010201000020000221000020000130032130032112002110910100101000010100000012701161112951910000100001000010010130033130033130033130033130033
3002413003297400000013001711940825400101001020000100001020238100005062144971480098211300130130032130032125489312626230010201000020000201000020000130032130032112002110910100101000010100000012701161112951910000100001000010010130033130033130033130033130035
3002413003297400000013001711940825400101001020000100001020000100005062148811480052811300130130032130032125489312626230010201000020000201000020000130032130032112002110910100101000010100000012701161212952010000100001000010010130033130033130033130033130033
3002413003297400000013001711940825400101001020000100001020000100005062144971480052811300130130032130032125489312626230010201000020000201000020000130032130032112002110910100101000010100000012701161112951910000100001000010010130033130033130033130033130133
3002413003297400000013001711940825400101001020000100001020000100005062144971480052811300130130032130032125489312626230010201000020000201000020000130032130032112002110910100101000010100000012701161212951910000100001000010010130033130033130033130033130033
3002413003297400000013001711940825400101001020000100001020000100005062144971480052811300130130032130032125489312626230010201000020000201000020000130032130032112002110910100101000010100000012701161112952310000100001000010010130033130033130033130033130033
3002413003297400000013001711940825400101001020000100001020000100005062144971480052811300130130032130032125489312626230010201000020000201000020000130032130032112002110910100101000010100000012702161112951910000100001000010010130033130033130033130033130033
3002413003297400000013001711940825400101001020000100001020000100005062144971480052811300133130032130032125489312626230010201000020000201000020000130032130032112002110910100101000010100000012701161112951910000100001000010010130033130033130033130033130033

Test 3: throughput

Count: 8

Code:

  scvtf h0, x8, #3
  scvtf h1, x8, #3
  scvtf h2, x8, #3
  scvtf h3, x8, #3
  scvtf h4, x8, #3
  scvtf h5, x8, #3
  scvtf h6, x8, #3
  scvtf h7, x8, #3
  mov x8, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.3339

retire uop (01)cycle (02)0318191e3f4f51schedule 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)simd prf full (72)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)9fa5ld unit uop (a6)acbranch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
16020426711199000266940251601001008000080000100800208001550011689511884163026695267092670966320666581601362008002080020200800208002026709267921180201100991001008000010008000001115117216002670680000800001002671026710267102671026710
16020426709200000266940251601001008000080000100800208001550011689511884163026690267092670966320666581601352008002080020200800208002026709267091180201100991001008000010008000001115117016002670680000800001002671026710267102671026710
16020426709200000266940251601001008000080000100800208001550011689511884163126690267092670966320666581601352008002080020200800208002026709267091180201100991001008000010008000001115117016002670680000800001002671026710267102671026710
16020426709200000266940251601001008000080000100800208001550011689511884163026690267092670966320666581601352008002080020200800208002426753268741180201100991001008000010008000001115117016002670980000800001002671026710267102671026710
16020426709200110266940251601001008000080000100800208001550011689511884163026690267092670966320666581601352008002080020200800208002026709267091180201100991001008000010008000001115117016002670680000800001002671026710267102671026710
16020426709199000266940251601001008000080000100800208001550011689511884163026690267092670966320666581601352008002080020200800208002026709267091180201100991001008000010008000001115117016002670680000800001002671026710267102671026710
16020426709200000266940251601001008000080000100800208001550011689511884163126690267092670966320666581601352008002080020200800208002026709267091180201100991001008000010008000001115117016002670680000800001002671026710267102671026710
16020426709200000266940251601001008000080000100800208001550011689511884163126690267092670966320666581601352008002080020200800208002026709267091180201100991001008000010008000001115117016002670680000800001002671026710267102671026710
16020426709200100266940251601001008000080000100800208001550011689511884163026690267092670966320666581601352008002080020200800208002026709267091180201100991001008000010008000001115117016002681980000800001002671026710267102671026710
16020426709200010266940251601001008000080000100800208001550011689511884163026690267092670966320666581601352008002080020200800208002026709267091180201100991001008000010008000001115117016002670680000800001002671026710267102671026710

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.3339

retire uop (01)cycle (02)03mmu table walk instruction (07)mmu table walk data (08)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)696d6emap stall dispatch (70)simd prf full (72)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)a5ld unit uop (a6)l1d cache writeback (a8)a9acc2cfl1i cache miss demand (d3)l1i tlb miss demand (d4)d5map dispatch bubble (d6)ddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1600242671220000001202669402516001010800008000010800008000050116827318840322669426713267136657036689160010208000080000208000080000267132672111800211091010800001000080000000050200071655267108000080000102671026714267102671526710
1600242670920000001202669822516001010800008000010800008000050116888018840322669426713267096653036689160010208038180000208000080000267132671311800211091010800001000080000103050200161665267068000080000102671426710267152671426714
1600242670920000001202670252516001010800008000010800008000050116888018744662669026713267136653036689160010208000080000208000080000267142670911800211091010800001000080000103050200171656267068000080000102739526715267142671426884
16002426713200000017402669402516001010800008000010800008000050116789018802602669026709267126656036693160010208000080000208000080000267092671311800211091010800001000080000103050200061656267068000080000102671426714267142671426714
160024267132000000002669822516001010800008000010800008000050118164718828532669027215267166654036689160010208000080000208000080000267092671311800211091010800001000080000103050200071665267108000080000102671026714267142671526714
160024267092000000002669802516001010800008000010800008000050116844018840122669026709267136653036689160010208000080000208000080000267092671411800211091010800001000080000000050200051677267108000080000102671426710267152671026714
160024267092000000002669822516001010800008000010800008000050116870718835252669526709267096653036689160010208000080000208000080000267142671311800211091010800001000080000103050200071675267098000080000102671426710267142671026714
16002426713200000012026698225160010108000080000108000080000501174994188285426694267092670966570366931600102080000800002080000800002671326714118002110910108000010000800001012050200051665267118000080000102671426714267142671026715
1600242671320000001202669822516001010800008000010800008000050117049318807942669426713267096657036689160010208000080000208000080000267132671311800211091010800001000080000103050200061665267068000080000102671526714267152671426714
1600242671420000001202669822516001010800008000010800008000050115708918840522669426710267136653036693160010208000080000208000080000267092671311800211091010800001000080000000050200061646267108000080000102671026714267142671426714