Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTNS (vector, 4H)

Test 1: uops

Code:

  fcvtns v0.4h, v0.4h
  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
1004303724156125472510001000100039816013018303730372414328951000100010003037303711100110001073216222629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073216222629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073216222629100030383038303830383038
1004303724216125472510001000100039816013018303730372414328951000100010003037303711100110000073216222629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073216222629100030383038303830383038
100430372396125472510001000100039816013018303730372414328951000100010003037303711100110000073216222629100030383038303830383038
10043037231284254725100010001000398160130183037303724143289510001000100030373037111001100002473216222629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073216222629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073216222629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073216222629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtns v0.4h, v0.4h
  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)031e3f4e51inst 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)9fa6a8a9acbranch mispredict (cb)cfd5d6ddinst fetch restart (de)e0ea? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1020430037233084295472510100100100001001000050042771600300183003730037282643287451010020410000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
1020430037232061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
1020430037233061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
1020430037233061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
10204300372330673295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
1020430037232961295472510100100100001001000050042771600300183003730037282648287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
1020430037233061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
10204300372330253295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
1020430037233061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
1020430037232061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)031e3f4e51inst 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
1002430037225015629547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640416662962910000103003830038300383003830038
100243003722506129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640616662962910000103003830038300383003830038
100243003722506129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640416552962910000103003830038300383003830038
100243003723306129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640416552962910000103003830038300383003830038
100243003722506129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001040640516652962910000103003830038300383003830038
1002430037225053629547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640516652962910000103003830038300383003830038
10024300372250612954725100101010000101000050427716030018300373003728286328767100102010000201000030037300371110021109101010000100168640616662962910000103003830038300383003830038
1002430037225072629547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640516552962910000103008130038300383003830038
1002430037224034929547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640516552962910000103003830038300383003830038
100243003722506129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640516552962910000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtns v0.4h, v8.4h
  fcvtns v1.4h, v8.4h
  fcvtns v2.4h, v8.4h
  fcvtns v3.4h, v8.4h
  fcvtns v4.4h, v8.4h
  fcvtns v5.4h, v8.4h
  fcvtns v6.4h, v8.4h
  fcvtns v7.4h, v8.4h
  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)030e3f51inst 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)9fa6a8acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80204200611550847258010810080008100800205006401320200200200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391550252258010810080008100800205006401320200200200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391550114258010810080008100800205006401320200200200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391550779258010810080008100800205006401320200200200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
8020420039155051258010810080008100800205006401320200200200392003999776999080120200800322008003220039200391180201100991001008000010001011151180160020036800001002004020040200402004020040
80204200391560202258010810080008100800205006401320200200200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391550179258010810080008100800205006401320200200200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
8020420039155030258010810080008100800205006401320200200200392003999776999080120200800322008003220039200391180201100991001008000010022311151180160020036800001002004020040200402004020040
80204200391560572258010810080008100800205006401320200200200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
8020420039155095258010810080008100800205006401320200200200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)03181e1f3a3f51inst 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)9fa8accfd5d6ddinst fetch restart (de)e0eaeb? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
800242003916700024125800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000502415162015200360080000102004020040200402004020040
800242003915500024125800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000502414161513200360080000102004020040200402004020040
800242003915500024125800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000502415161315200360080000102004020040200402004020040
800242003915600024125800101080000108000050640000120020200392003999963100198001020800002080000200392007511800211091010800001000502418161315200360080000102004020040200402004020040
800242003915500024125800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000502415161515200360080000102004020040200402004020040
800242003915500024625800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000502415161415200360080000102004020040200402004020040
800242003915500024125800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000502412161513200360080000102004020040200402004020040
800242003915500021272580010108000010800005064000012002020039200399996310019800102080000208000020039200391180021109101080000100050241416817200360080000102004020040200402004020040
80024200391550002412580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050241316915200360080000102004020040200402004020040
800242003915500024125800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000502416161416200360080000102004020040200402004020040