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, integer, S from W)

Test 1: uops

Code:

  scvtf s0, w0
  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
2004376203610252000100010001000100014075228201357376376723109200010001000100010003763761110011000100000732162137310001000377377377377378
2004376203610252000100010001000100014075228200357376376723109200010001000100010003763791110011000100000732162237310001000377377380377379
2004376303610252000100010001000100014075228200357376376723109200010001000100010003763761110011000100000732162237310001000377377377377377
2004376203610252000100010001000100014075228201357376376723109200010001000100010003763761110011000100000732162237310001000377377377377377
2004376303610252000100010001000100014075228200357376376723109200010001000100010003763761110011000100000732162237310001000377377377377377
2004376203610252000100010001000100014075228200357376376723109200010001000100010003773761110011000100000732162237310001000377377377377377
2004376203610252000100010001000100014075228200357376376723109200010001000100010003773761110011000100000732162237310001000377377377377377
2004376303612252000100010001000100014075228200357376376723109200010001000100010003763761110011000100000732162237310001000377377377377377
2004376303610252000100010001000100014075229301358376376723109200010001000100010003763791110011000100000732162237310001000377377377377377
2004376203610252000100010001000100014075228200357376376723109200010001000100010003763761110011000100000732162237310001000377377377377377

Test 2: Latency 1->2 roundtrip

Code:

  scvtf s0, w0
  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 instruction (07)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 miss (a1)ld unit uop (a6)l1d cache writeback (a8)a9acc2cfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
3020413003297400000013001711940925401001010020000100001002000010000500621449714802709013001301300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000100005000131016163212951910000100001000010100130033130033130033130033130033
3020413003297400000013001711940825401001010020000100001002000010000500621449714802709013001301300321300321254663126240301002001000020000200100002012713003213003211202011009910010100100001000100000000131012162212951910000100001000010100130037130033130033130033130033
3020413003297410000013001711940825401001010020000100001002000010000500621449714802709013001331300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000100000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297410000013001711940825401001010020000100001002000010000500621449714802709013001301300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000100000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297400000013001711940825401001010020000100001002000010000500621449714802821013001301300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000100000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297400009013001711940825401001010020000100001002000010000500621449714802709013001401300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000100000000131012162212951910000100001000010100130033130033130033130033130033
30204130032974000000130017119476254010010100200001000010020116100005006214497148027090130013013003313003212550915126240301002001000020000200100002000013003213003211202011009910010100100001000100033000131012162212951910000100001000010100130033130033130033130033130068
3020413003297400000013001711940825401001010020000100001002000010000500621449714802709013001301300321300331254663126240301002001000020000200100002000013003213003211202011009910010100100001003100001285682131016162212951910000100001000010100130033130033130033130033130033
3020413003297400000013001711940925401001010020000100001002000010000500621464114802709013001301300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000100000030131002162212951910000100001000010100130033130033130033130033130033
3020413003297400000013001811940825401001010020000100001002000010000500621449714802709013001301300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000100000000131012162212951910000100001000010100130033130033130033130033130033

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0032

retire uop (01)cycle (02)03l2 tlb miss instruction (0a)1e3f4f51schedule 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)5f60696d6emap 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)acc2branch 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
3002413003297401213001711940825400101001020000100001020000100005062145931480052800130013130032130032125489312626430010201000020000201000020000130032130032112002110910100101000010100000600012705165312951910000100001000010010130040130036130033130035130033
3002413003297401213001711941025400101001020000100001020000100005062144971480052800130013130032130032125491312626230010201000020000201000020000130032130032112002110910100101000010100001300012705163512951910000100001000010010130077130036130033130033130033
300241300329740013001711940825400101001020000100001020000100005062144971480052800130016130033130032125489312626230010201000020000201000020000130032130032112002110910100101000010100001300012724164512951910000100001000010010130049130039130034130033130036
3002413003297401213001711940825400101001020000100001020000100005062145931480052800130016130032130032125489312626230012201000020000201000020000130032130032112002110910100101000010100001300012706165412951910000100001000010010130034130036130034130033130033
3002413003297401213001711940825400101001020000100001220000100006062144971480052800130013130032130033125491312626230010201000020000201000020000130032130032112002110910100101000010100001300012705163512952010000100001000010010130120130195130046130034130033
3002413003297401213001711940825400101001020000100001020000100005062144971480075200130014130034130033125489312626230010201000020000201000020000130032130032112002110910100101000010100000300012704167512951910000100001000010010130071130034130033130033130034
3002413003297401213001811940825400101001020000100001020000100005062144971480052800130013130033130032125489312626230010201000020000201000020000130032130032112002110910100101000010100001000012705165612951910000100001000010010130037130033130033130033130036
3002413003397401213001711940825400101001020000100001020000100005062144971480087600130013130032130033125489312626230010201000020000201000020000130032130032112002110910100101000010100001300012704164612951910000100001000010010130033130033130034130036130033
3002413003297401213001711940825400101001020000100001020000100005062144971480052800130013130034130032125490312626630010201000020000201000020000130032130032112002110910100101000010100001300012704164512951910000100001000010010130033130033130033130033130033
3002413003297401213001711941025400101001020000100001020000100005062144971480052800130013130032130035125489312626230010201000020000201000020000130032130032112002110910100101000010100000000012704164512951910000100001000010010130360130050130034130037130033

Test 3: throughput

Count: 8

Code:

  scvtf s0, w8
  scvtf s1, w8
  scvtf s2, w8
  scvtf s3, w8
  scvtf s4, w8
  scvtf s5, w8
  scvtf s6, w8
  scvtf s7, w8
  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)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)696d6emap 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)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
1602042671620000201202669902516010010080000800001008002080015500115956818841632669426713267136636666621601352008002480024200800248002026713267131180201100991001008000010080000031115117016002671080000800001002671426715267102671426714
1602042670920000001202669922516010010080000800001008002080015500117053218841632669426714267136636666621601352008002080020200800248002426713267091180201100991001008000010080000131115117016002671080000800001002671426710267142671526714
160204267141990000002669822516010010080000800001008002080015500116848218791302669626714267106624966511601412008002780023200800238002326714267141180201100991001008000010080000032225127124112671180000800001002671626715267162671526711
16020426714200000012026700325160100100800008000010080023800175001168398188273126696267142671566211066491601412008002380023200800238002326715267101180201100991001008000010080000132225128124112671180000800001002671426711267112671526715
1602042671020000001202677432516010010080000800001008002380018500117412918838312669526714267106624966471601412008002380023200800238002326714267101180201100991001008000010080000102225127124112671180000800001002671526715267112671526715
1602042671420000001202670822516010010080000800001008002380018500117502918840582669126714267146625106646160141200800238002320080023800232671526715118020110099100100800001008000019052225128242112686580000800001002688826892268882689127009
160204274052011111291208270321229516062210080260800001008020880017500117476118837622669626714267136625966491601412008002380023200800238002326717267131180201100991001008000010080000232225128124112671180000800001002671526711267152671526715
1602042671420000001202683822516010010080000800001008002380017500118028218834602669126714267136621966501601412008002780023200800278002326713267151180201100991001008000010080000102225127124112671280000800001002671526714267152671126716
1602042671020000001202670332516010010080000800001008002380018500116742718817342669626710267146625966461601412008002380023200800238002326715267151180201100991001008000010080000132225127124112671180000800001002671526715267152671126711
1602042671420000001202669922516010010080000800001008002380018500116957118833692669526710267136625966501601422008002380023200800238002726714267141180201100991001008000010080000102225127124112671180000800001002672726716267152671126715

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)03l1i tlb fill (04)mmu 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)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)ld unit uop (a6)l1d cache writeback (a8)a9accfd0d5map dispatch bubble (d6)ddfetch restart (de)e0ea? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1600242670920000000002672302516001010800008000010800008000050116888018840322669326710267146656036689160010208000080000208000080000267092670911800211091010800001008000000050200216222670608000080000102671026710267102671026710
1600242670920000000002671402516001010800008000010800008000050116888018840322669026709267096653036689160010208000080000208000080000267092670911800211091010800001008000000050200116112670608000080000102671026710267102671026710
1600242670920000000002670102516001010800008000010800008000050116888018840322669026709267096653036689160010208000080000208000080000267092670911800211091010800001008000000050200116222670608000080000102671026710267102671026710
1600242670920000000002669402516001010800008000010800008000050116888018840322669026709267096653036689160010208000080000208000080000267092670911800211091010800001008000000050200116112670608000080000102671026710267102671026710
1600242670920000000002670202516001010800008000010800008000050116888018840322669026709267096656036689160010208000080000208000080000267092670911800211091010800001008000000050200116112670608000080000102671026710267102671026710
1600242670920000000002669402516001010800008000010800008000050116888018840322669026709267096653036689160010208000080000208000080000267092670911800211091010800001008000000050200116112670608000080000102671426716267372687826710
1600242670920000040002669602516001010800008000010800008000050116888018840322669026709267096653036689160010208000080000208000080000267092670911800211091010800001008000000050200216112670608000080000102671026710267112671226710
1600242671320000000002670502516001010800008000010800008000050116888018840322669026709267096653036689160010208000080000208000080000267092670911800211091010800001008000000050200116112670608000080000102671026710267102671026710
1600242670920000000002670402516001010800008000010800008000050116888018840322669026709267096653036689160010208000080000208000080000267092670911800211091010800001008000000050200116112670608000080000102671026710267102671026710
1600242670919900000002669802516001010800008000010800008000050116888018840322669026709267096653036689160010208000080000208000080000267092670911800211091010800001008000000050200116112670608000080000102671026710267102671026710