Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTPS (scalar, D to D)

Test 1: uops

Code:

  fcvtps d0, d0
  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)03070a1e3a3f4e51inst issue (52)~issue fp/simd (54)~dispatch fp/simd (57)huge thing fp/simd (5b)696d6edispatch 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
10043037241102682547251000100010003981603018303730372414328951000100010003037303711100110000077516442629100030383038303830383038
10043037231102682547251000100010003981603018303730372414328951000100010003037303711100110000077416442629100030383038303830383038
10043037241102682547251000100010003981603018303730372414328951000100010003037303711100110002077416442629100030383038303830383038
10043037231102682547251000100010003981603018303730372414328951000100010003037303711100110003077416442629100030383038303830383038
10043037241102682547251000100010003981603018303730372414328951000100010003037303711100110000077416442629100030383038303830383038
10043037231102682547251000100010003981603018303730372414328951000100010003037303711100110000077416442629100030383038303830383038
100430372311242682547251000100010003981603018303730372414328951000100010003037303711100110000077416442629100030383038303830383038
10043037231102682547251000100010003981603018303730372414328951000100010003037303711100110000077416442629100030383038303830383038
100430372311021102547251000100010003981603018303730372414328951000100010003037303711100110001377416442629100030383038303830383038
10043037231102682547251000100010003981603018303730372414328951000100010003037303711100110000077416442629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtps d0, d0
  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)03080b18191e1f3f4e51inst 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)9fa0a1a6a8acc2cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10204300372320000308229547251010010010000100100005004277160030018030037300372826832874510100200100002001000030037300371110201100991001001000010000000071011611296330100001003003830038300383003830038
102043003723200003011029547251010010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010000000071011611296520100001003003830038300383003830038
10204300372330000306129547251010010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010000003071011611296330100001003013630038300383003830038
10204300372330000144074729547441012010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010000013071011611296330100001003003830038300383003830038
10204300372320000308229547251010010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010000000071031611296330100001003003830038300383003830038
102043003723200003023729547251010010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010000006071011611296330100001003003830038300383003830038
10204300372330000308229547251010010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010000013071011611296330100001003003830038300383003830038
10204300372330000308229547251010010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010000000071011611296330100001003003830038300383003830038
10204300372330000420140295472510100100100001001000050042771600300180300373003728264328745101002001000020010000300373003711102011009910010010000100000139071011611296330100001003003830038300383003830038
1020430037233000012099029547251010010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010000000071011611296333100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)03080b191e1f3a3f4e51inst 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)9fa0a1a7a8a9accfd5d6ddinst fetch restart (de)e0eb? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
100243003723300012006129538251001010100001010000504278512130018300373003728286328767100102010044201000030037300371110021109101010000100003006404165529629010000103003830038300383003830038
100243003723300012006129547251001010100001010000504277160130162300373003728286328767100102010000201000030037300371110021109101010000100001007325164429629010000103003830038300383003830038
1002430037232000132008229547431001010100001110000504277160130018300373003728286328767100102010000201000030037300371110021109101010000102201406406163529629010000103003830038300383003830038
100243003723200012006129547251001010100001010000504277160130018300373003728286328767103142010000201000030037300371110021109101010000100000006405165529629010000103003830038300383003830038
1002430037233000120010329529251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101010000100000006406166629629010000103003830038300383003830038
1002430037233010088084295472510010101000010100005042771600300183003730037282861128767100102010000201000030037300371110021109101010000100002006404165629629010000103003830038300383003830038
10024300372330000006129547251001010100001010000504277160130018300373003728286328767100102010492201000030037300371110021109101010000100000006406165629629010000103003830038300383007830038
10024300372330000006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006405165529629010000103003830038300383003830038
10024300372250003006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006405165429629010000103003830038300383003830038
100243003722500000044129547251001812100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100009006406166529629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtps d0, d8
  fcvtps d1, d8
  fcvtps d2, d8
  fcvtps d3, d8
  fcvtps d4, d8
  fcvtps d5, d8
  fcvtps d6, d8
  fcvtps d7, d8
  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)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)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)9fa8acc5branch mispredict (cb)cdcfd6inst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8020420039155213025801081008000810080020500640132020020200392003999766999080120200800322008003220039200391180201100991001008000010000111511816020036800001002004020040200402004020040
8020420039155183025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000111511816020036800001002004020040200402004020040
8020420039155213025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000111511816020036800001002004020040200402004020040
8020420039155213025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000111511816020036800001002004020040200402004020040
8020420039155273025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000111511816020036800001002004020040200402004020040
802042003915603025801081008010810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000111511816020036800001002004020040200402004020040
802042003915503025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000111511816020036800001002004020040200402004020040
8020420039155273025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000111511816020036800001002004020040200402004020040
802042003915503025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010013111517316020036800001002004020040200402004020040
802042003915603025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000111511816020036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)0304070b1e3f51inst 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)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8002420051155100040258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010005020316112003680000102004020040200402004020040
80024200391550004840258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010005020116112003680000102004020040200402004020040
80024200391550005440258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010005020116112003680000102004020040200402004020040
80024200391550004296258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010005054116112003680000102004020040200402004020040
8002420039155000040258001010800001080106506400000200202003920039999631001980010208000020800002003920039118002110910108000010005020116112003680000102004020040200402004020040
80024200391550001840258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010005020116112003680000102004020040200402004020040
80024200391550003940258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010005020116112003680000102004020040200402004020040
80024200391550003940258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010005020116112003680000102004020040200402004020040
8002420039155000040258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010005020116112003680000102004020040200402004020040
800242003915900014743258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010005020116112003680000102004020040200402004020040