Apple M1 Microarchitecture Research by Dougall Johnson

Firestorm: Overview | Base Instructions | SIMD and FP Instructions
Icestorm:  Overview | Base Instructions | SIMD and FP Instructions

FCVTZS (vector, fixed-point, 8H)

Test 1: uops

Code:

  fcvtzs v0.8h, v0.8h, #3
  movi v0.16b, 1
  movi v1.16b, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 1.000

Integer unit issues: 0.000

Load/store unit issues: 0.000

SIMD/FP unit issues: 1.000

retire (01)cycle (02)031e3f4e51inst issue (52)~issue fp/simd (54)~dispatch fp/simd (57)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op fp/simd (7e)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst neon or fp (9a)a8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073216112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723010325472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtzs v0.8h, v0.8h, #3
  movi v0.16b, 1
  movi v1.16b, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)03080b18191e1f3a3f4e51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696b6d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa1a6a7a8a9acc2cfd5d6ddinst fetch restart (de)e0? int output thing (e9)eb? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10204300372330000000612954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000003000710216112963300100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716013001803003730085282643287451010020010000200100003003730037111020110099100100100001000000000710116112963300100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710116112963300100001003003830038300383003830038
102043003723200000006129547251010010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010000032060710116112963300100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716013001803003730037282648287451010020010000200100003003730037111020110099100100100001000004000710116112963300100001003003830038300383003830038
102043003723300000001562954725101001001000010010000500427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710116112963300100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710116112963300100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710116102963300100001003003830038300383003830069
10204300372320000000892954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000001000710116312963300100001003003830038300383022930038
102043003723200001200612951144101001001000810010000500427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000004030710116112963300100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)031e3a3f4e51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10024300372250061295472510010101000010100005042771603001830037300372828632876710010201000020100003003730037111002110910101000010253640516552962910000103003830038300383003830038
1002430037225006129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640516662962910000103003830038300383003830038
1002430037225006129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640516652962910000103003830038300383003830038
1002430037225006129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640416562962910000103003830038300383003830038
1002430037225006129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001010640616652962910000103003830038300383003830038
100243003722500156295472510010101000010100005042771603001830037300372828632876710010201000020100003003730037111002110910101000010480640616552962910000103003830038300383003830038
1002430037225016129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001016640616662962910000103003830038300383003830038
1002430037225006129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640616562962910000103003830038300383003830038
1002430037225006129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640616652962910000103003830038300383003830038
10024300372250061295472510010101000010100005042771603001830037300372828632876710010201000020100003003730037111002110910101000010290640416662962910000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtzs v0.8h, v8.8h, #3
  fcvtzs v1.8h, v8.8h, #3
  fcvtzs v2.8h, v8.8h, #3
  fcvtzs v3.8h, v8.8h, #3
  fcvtzs v4.8h, v8.8h, #3
  fcvtzs v5.8h, v8.8h, #3
  fcvtzs v6.8h, v8.8h, #3
  fcvtzs v7.8h, v8.8h, #3
  movi v8.16b, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.2505

retire (01)cycle (02)03091e1f3f51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa0a6a7a8a9acc2c5branch mispredict (cb)cdcfd5d6inst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8020420039156000896258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000000011151184160200360800001002004020040200402004020040
802042003915500030258010810080008100800205006409760200202003920039997769990801202008003220080032200392003911802011009910010080000100000000011151180160200360800001002004020040200402004020040
8020420039155012030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000000011151180160200360800001002004020040200402004020040
802042003915600051258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000000011151180160200360800001002004020040200402004020040
8020420039156098830258010810080008100800205006401321200202003920039997769990801202008003220080032201432003911802011009910010080000100000200011151180160200781800001002004020040200402004020040
802042003915500030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100400000011151180160200360800001002004020040200402004020040
802042003915500030258010810080008100801285006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000300011151180160200360800001002004020040200402004020040
802042003915600030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000000011151180160200360800001002004020040200402004020040
8020420039156012030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000000011151180160200360800001002004020040200402004020040
802042003915500030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000000011151180160200360800001002004020040200402004020040

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.2505

retire (01)cycle (02)030a181e1f3a3f51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa0a1a8accfd5d6ddinst fetch restart (de)e0eb? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
800242005015500000692580010108000010800005064000012002020039200399996310019800102080000208000020039200391180021109101080000100000502022169920036080000102004020040200402004020040
800242003915620000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100000502071681120036080000102004020040200402004020040
80024200391552000040258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010001050201116101020036080000102004020040200402004020040
80024200391552000040258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010000050209167920036080000102004020040200402004020040
80024200391562000040258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010000875020101610720036080000102004020040200402004020040
80024200391552000040258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010001050205169720036080000102004020040200402004020040
800242003915620000135258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010001050208168720036080000102004020040200402004020040
800242003915520000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100000502081671020036080000102004020040200402004020040
80024200391562000040258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010000050207169720036080000102004020040200402004020040
80024200391553000040258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010000050209167920036080000102004020040200402004020040