Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTPS (vector, 2D)

Test 1: uops

Code:

  fcvtps v0.2d, v0.2d
  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
100430372308225472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372406125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723010325472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303724014525472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtps v0.2d, v0.2d
  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)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)9fa8a9accfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1020430037233000012001032954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372320000000612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
102043003723300000003462954725101001001000010010000500427716013002030037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010010071011611296330100001003003830038300383003830038
10204300372320000000612954725101001001000010010000500427716003001830084300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611297050100001003003830038300383003830038
10204300372320000000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)030b1e1f3f4e51inst 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)9fa1a8a9acbbc2cfd5d6ddinst fetch restart (de)e0ea? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
100243003723200072629547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006404165529629010000103003830038300383003830038
10024300372330006129547251001010100001010000504277160030018300373003728286328767100102010000201000030180300371110021109101010000100000006404165629629010000103003830038300383003830038
10024300372330006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006405165529629010000103003830038300383003830038
10024300372330006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006406164429629010000103003830038300383003830038
10024300372320606129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006405166529629010000103003830038300713003830038
10024300372320006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006404164629629010000103003830038300383003830038
10024300372330006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006405165529629010000103003830038300383003830038
10024300372250006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006405166629629010000103003830038300383003830038
10024300372250006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006404164629629010000103003830038300383003830038
10024300372250006129547251001010100071010000504277160030018300373003728286328767100102010000201000030037300372110021109101010000100000006406166629629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtps v0.2d, v8.2d
  fcvtps v1.2d, v8.2d
  fcvtps v2.2d, v8.2d
  fcvtps v3.2d, v8.2d
  fcvtps v4.2d, v8.2d
  fcvtps v5.2d, v8.2d
  fcvtps v6.2d, v8.2d
  fcvtps v7.2d, v8.2d
  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)0308090b181e3f51inst 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)9fa6a8acc2c5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80204200571550000072258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000011151183162120036800001002004020040200402004020040
80204200391550000030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000011151182160020036800001002004020040200402004020040
80204200391560000030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100010011151181161220036800001002004020040200402004020040
80204200391560000030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100003011151181161120036800001002004020040200402004020040
80204200391550000030258050510080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100003011151181161220036800001002004020040200402004020040
80204200391550000030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100003011151182162220036800001002004020040200402004020040
80204200391550000030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100010011151181162120036800001002004020040200402004020040
80204200391560000030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000011151181161220036800001002004020040200402004020040
80204200391550000030258010810080008100800205006401320200202003920039997769990801202008003620080032200392003911802011009910010080000100000011151182162320036800001002004020040200402004020040
80204200391550000030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000011151180162220036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)031e3f51inst 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)72scheduler 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)9fa8accdcfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
800242005015504025800101080000108000050640000020020200392003999960310019800102080000208000020039200391180021109101080000103305020291623242003680000102004020040200402004020040
8002420039156082258001010800001080000506400001200202003920039999603100198001020800002080000200392003911800211091010800001002705020231625262003680000102004020040200402004020040
8002420039155040258001010800001080000506400000200202003920039999603100198001020800002080000200392003911800211091010800001051005020281616282003680000102004020040200402004020040
8002420039156040258001010800001080000506400000200202003920039999603100198001020800002080000200392003911800211091010800001006605020284813282003680000102004020040200402004020040
800242003915504025800101080000108000050640000120020200392003999960310019800102080000208000020039200391180021109101080000102305020261625152003680000102004020040200402004020040
8002420039155040258001010800001080000506400000200202003920039999603100198001020800002080000200392003911800211091010800001003305020271627272003680000102004020040200402004020040
8002420039155040258001010800001080000506400000200202003920039999603100198001020800002080000200392003911800211091010800001001205020141627142003680000102004020040200402004020040
800242003915508225800101080000108000050640000020020200392003999960310019800102080000208000020039200391180021109101080000102005020271613262003680000102004020040200402004020040
800242003915504025800101080390108000050640000020020200392003999960310019800102080000208000020039200391180021109101080000100005020271631272003680000102004020040200402004020040
8002420039155040258001010800001080000506400000200202003920039999603100198001020800002080000200392003911800211091010800001044005020151625142003680000102004020040200402004020040