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

FCVTMS (scalar, H to X)

Test 1: uops

Code:

  fcvtms x0, h0
  mov x0, 1
  mov x1, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 2.000

Issues: 3.000

Integer unit issues: 1.001

Load/store unit issues: 0.000

SIMD/FP unit issues: 2.000

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch simd uop (57)ldst uops in schedulers (5b)dispatch uop (78)map simd uop (7e)map simd uop inputs (81)? int output thing (e9)? simd retires (ee)? int retires (ef)
20041037300110012000200011000200020002000100110001000
20041037300110012000200011000200020002000100110001000
20041037300110012000200011000200020002000100110001000
20041037300110012000200011000200020002000100110001000
20041037300110012000200011000200020002000100110001000
20041037300110012000200011000200020002000100110001000
20041037300110012000200011000200020002000100110001000
20041037300110012000200011000200020002000100110001000
20041037300110012000200011000200020002000100110001000
20041037300110012000200011000200020002000100110001000

Test 2: Latency 1->2 roundtrip

Code:

  fcvtms x0, h0
  fmov d0, x0
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 10.0032

retire uop (01)cycle (02)schedule 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)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)? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)
3020410003240101101012000010000100200001000030015467862578206301002001000220004200100022000410001100001000010100
3020410003240101101012000010000100200001000030015467962578206301002001000120003200100012000310001100001000010100
3020410003240101101012000010000100200001000030015468922578362301002001000120003200100012000310001100001000010100
3020410003240101101012000010000100200001000030015467862578206301002001000220004200100012000310001100001000010100
3020410003240101101012000010000100200001000030015467962578206301002001000120003200100012000310001100001000010100
3020410003240101101012000010000100200001000030015467962578206301002001000120003200100012000310001100001000010100
3020410003240101101012000010000100200001000030015467962578206301002001000120003200100012000310001100001000010100
3020410003240101101012000010000100200001000030015467962578206301002001000120003200100012000310001100001000010100
3020410003240101101012000010000100200001000030015467962578206301002001000120003200100012000310001100001000010100
3020410003240101101012000010000100200001000030015467962578206301002001000120003200100012000310001100001000010100

1000 unrolls and 10 iterations

Result (median cycles for code): 10.0032

retire uop (01)cycle (02)schedule 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)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)? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)
300241000354001110011200001000010200001000030154633625782063001020100022000420100002000010001100001000010010
300241000324001110011200001000010200001000030154634625782063001020100002000020100002000010001100001000010010
300241000324001110011200001000010200001000030154634625782063001020100002000020100002000010001100001000010010
300251000644001710012200041000110200301000030154634625782063001020100002000020100002000010001100001000010010
300251001164001710012200041000110200301000030154644325783623001020100002000020100002000010001100001000010010
300241000344001110011200001000010200001000030154634625782063001020100002000020100002000010001100001000010010
300241000324001110011200001000010200001000030154634625782063001020100002000020100002000010001100001000010010
300241000324001110011200001000010200001000030154634625782063001020100002000020100192004110002100001000010010
300241000324001110011200001000010200001000030154634625782063001020100002000020100202003910002100001000010010
300241000344001110011200001000010200001000030154634625782063001020100002000020100002000010001100001000010010

Test 3: throughput

Count: 8

Code:

  fcvtms x0, h8
  fcvtms x1, h8
  fcvtms x2, h8
  fcvtms x3, h8
  fcvtms x4, h8
  fcvtms x5, h8
  fcvtms x6, h8
  fcvtms x7, h8
  mov x8, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 1.0005

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule simd uop (54)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)dispatch uop (78)map int uop (7c)map ldst uop (7d)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)? int output thing (e9)? simd retires (ee)? int retires (ef)
1602048004124010380101160002100160008030008800411601082000160012200160012800018000080100
1602048003724010380101160002100160008030008800411601082000160012200160012800018000080100
1602048003724010380101160002100160008030008800411601082000160012200160012800018000080100
1602048003724010380101160002100160008030008800411601082000160012200160012800018000080100
1602048003724010380101160002100160008030008800411601082000160012200160012800018000080100
1602048003724010380101160002100160008030008800411601082000160012200160012800018000080100
1602048003724010380101160002100160008030008800411601082000160012200160012800018000080100
1602048003724010380101160002100160008030008800411601082000160012200160012800018000080100
1602048003724010380101160002100160008030008800411601082000160012200160012800018000080100
1602058007424015580115160040100160058030008800411601082000160012200160012800018000080100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 1.0005

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)? int output thing (e9)? simd retires (ee)? int retires (ef)
160024800662400138001116000210160008308800001600102016000020160000800018000080010
160024800372400118001116000010160000308800001600102016000020160000800018000080010
160024800372400118001116000010160000308800001600102016000020160000800018000080010
160024800372400118001116000010160000308800001600102016000020160000800018000080010
160024800372400118001116000010160000308800001600102016000020160068800158000080010
160024800372400118001116000010160000308800001600102016000020160000800018000080010
160024800372400118001116000010160000308800001600102016000020160000800018000080010
160024800372400118001116000010160000308800001600102016000020160000800018000080010
160024800372400118001116000010160000308800001600102016000020160000800018000080010
160024800372400118001116000010160000308800001600102016000020160068800158000080010