How to use the FPU STM32H723

[ENort.1]

I have these math functions that I would like to use the FPU for:

sqrtf()

cosf()

sinf()

fabs()

atan2f()

floorf()

ceilf()

truncf()

roundf()

How do I enable the FPU in the STM32H723? I see it is selected in the settings but not sure if it is enabled or not.

Do the above-listed functions call the FPU to process them or am I missing something? I need my application to run as fast as possible without using the software math libraries. Any help would be greatly appreciated.

[Tesla DeLorean]

There's a command line option, you can check that.

You can generate a listing file and inspect that.

The compiler can use intrinsic math functions, and can pull a library containing compound functionality.

The FPU isn't advanced, it doesn't support transcendental math functions, and it doesn't carry higher intermediate precision (ie not an 80x87 or 6888x type FPU)

You can always code your own math routines using the HW/FPU

You'll need to check the docs on ST's CORDIC functions.

GNU Double Precision, passed in FPU registers

-mfpu=fpv5-d16 -mfloat-abi=hard

[Tesla DeLorean]

Tends to require wrapping, here KEIL/REALVIEW

 __hardfp_sqrtf
 0x00000000: b510 .. PUSH {r4,lr}
 0x00000002: ed2d8b02 -... VPUSH {d8}
 0x00000006: eeb18ac0 .... VSQRT.F32 s16,s0
 0x0000000a: ee180a10 .... VMOV r0,s16
 0x0000000e: f0204000 ..@ BIC r0,r0,#0x80000000
 0x00000012: f1c040ff ...@ RSB r0,r0,#0x7f800000
 0x00000016: 0fc0 .. LSRS r0,r0,#31
 0x00000018: d00a .. BEQ {pc}+0x18 ; 0x30
 0x0000001a: ee100a10 .... VMOV r0,s0
 0x0000001e: f0204000 ..@ BIC r0,r0,#0x80000000
 0x00000022: f1c040ff ...@ RSB r0,r0,#0x7f800000
 0x00000026: 0fc0 .. LSRS r0,r0,#31
 0x00000028: bf04 .. ITT EQ
 0x0000002a: 2001 . MOVEQ r0,#1
 0x0000002c: f7fffffe .... BLEQ __set_errno
 0x00000030: eeb00a48 ..H. VMOV.F32 s0,s16
 0x00000034: ecbd8b02 .... VPOP {d8}
 0x00000038: bd10 .. POP {r4,pc}
 
 __hardfp_cosf
 0x00000000: 4a44 DJ LDR r2,[pc,#272] ; [0x114] = 0x7e921fb6
 0x00000002: ee101a10 .... VMOV r1,s0
 0x00000006: b508 .. PUSH {r3,lr}
 0x00000008: ebb20f41 ..A. CMP r2,r1,LSL #1
 0x0000000c: 4668 hF MOV r0,sp
 0x0000000e: d926 &. BLS {pc}+0x50 ; 0x5e
 0x00000010: f04f40e6 O..@ MOV r0,#0x73000000
 0x00000014: ebb00f41 ..A. CMP r0,r1,LSL #1
 0x00000018: bf94 .. ITE LS
 0x0000001a: 2000 . MOVLS r0,#0
 0x0000001c: f04f30ff O..0 MOVHI r0,#0xffffffff
 0x00000020: 9000 .. STR r0,[sp,#0]
 0x00000022: 9800 .. LDR r0,[sp,#0]
 0x00000024: eddf0a3c ..<. VLDR s1,[pc,#240] ; [0x118] = 0x3f800000
 0x00000028: 2800 .( CMP r0,#0
 0x0000002a: db5f _. BLT {pc}+0xc2 ; 0xec
 0x0000002c: f0100f01 .... TST r0,#1
 0x00000030: d045 E. BEQ {pc}+0x8e ; 0xbe
 0x00000032: ee600a00 `... VMUL.F32 s1,s0,s0
 0x00000036: f0100f02 .... TST r0,#2
 0x0000003a: ed9f2a38 ..8* VLDR s4,[pc,#224] ; [0x11c] = 0x394c6d33
 0x0000003e: eddf1a38 ..8. VLDR s3,[pc,#224] ; [0x120] = 0x3c0882da
 0x00000042: ed9f1a38 ..8. VLDR s2,[pc,#224] ; [0x124] = 0xbe2aaaa0
 0x00000046: ee401ac2 @... VMLS.F32 s3,s1,s4
 0x0000004a: ee001aa1 .... VMLA.F32 s2,s1,s3
 0x0000004e: ee211a20 !. . VMUL.F32 s2,s2,s1
 0x00000052: eef00a40 ..@. VMOV.F32 s1,s0
 0x00000056: ee400a01 @... VMLA.F32 s1,s0,s2
 0x0000005a: d02d -. BEQ {pc}+0x5e ; 0xb8
 0x0000005c: e040 @. B {pc}+0x84 ; 0xe0
 0x0000005e: 4a32 2J LDR r2,[pc,#200] ; [0x128] = 0x46490e49
 0x00000060: f0214300 !..C BIC r3,r1,#0x80000000
 0x00000064: 429a .B CMP r2,r3
 0x00000066: d93e >. BLS {pc}+0x80 ; 0xe6
 0x00000068: f0114f00 ...O TST r1,#0x80000000
 0x0000006c: eddf0a2f ../. VLDR s1,[pc,#188] ; [0x12c] = 0x3f22f983
 0x00000070: ed9f1a2f ../. VLDR s2,[pc,#188] ; [0x130] = 0x4b000000
 0x00000074: ee600a20 `. . VMUL.F32 s1,s0,s1
 0x00000078: bf08 .. IT EQ
 0x0000007a: ee700a81 p... VADDEQ.F32 s1,s1,s2
 0x0000007e: ee700ac1 p... VSUB.F32 s1,s1,s2
 0x00000082: bf18 .. IT NE
 0x00000084: ee700a81 p... VADDNE.F32 s1,s1,s2
 0x00000088: ed9f3a2a ..*: VLDR s6,[pc,#168] ; [0x134] = 0x3fc90000
 0x0000008c: eddf2a2a ..** VLDR s5,[pc,#168] ; [0x138] = 0x39fda000
 0x00000090: ed9f2a2a ..** VLDR s4,[pc,#168] ; [0x13c] = 0x33a22000
 0x00000094: eddf1a2a ..*. VLDR s3,[pc,#168] ; [0x140] = 0x2c34611a
 0x00000098: ee000ac3 .... VMLS.F32 s0,s1,s6
 0x0000009c: eebd1ae0 .... VCVT.S32.F32 s2,s1
 0x000000a0: ee000ae2 .... VMLS.F32 s0,s1,s5
 0x000000a4: ee110a10 .... VMOV r0,s2
 0x000000a8: f0000003 .... AND r0,r0,#3
 0x000000ac: 9000 .. STR r0,[sp,#0]
 0x000000ae: ee000ac2 .... VMLS.F32 s0,s1,s4
 0x000000b2: ee000ae1 .... VMLS.F32 s0,s1,s3
 0x000000b6: e7b4 .. B {pc}-0x94 ; 0x22
 0x000000b8: eef10a60 ..`. VNEG.F32 s1,s1
 0x000000bc: e010 .. B {pc}+0x24 ; 0xe0
 0x000000be: ee200a00 ... VMUL.F32 s0,s0,s0
 0x000000c2: ed9f2a20 .. * VLDR s4,[pc,#128] ; [0x144] = 0xbab23ab9
 0x000000c6: f0100f02 .... TST r0,#2
 0x000000ca: eddf1a1f .... VLDR s3,[pc,#124] ; [0x148] = 0x3d2a9fca
 0x000000ce: ed9f1a1f .... VLDR s2,[pc,#124] ; [0x14c] = 0xbeffffdd
 0x000000d2: ee401a02 @... VMLA.F32 s3,s0,s4
 0x000000d6: ee001a21 ..!. VMLA.F32 s2,s0,s3
 0x000000da: ee400a01 @... VMLA.F32 s1,s0,s2
 0x000000de: d1eb .. BNE {pc}-0x26 ; 0xb8
 0x000000e0: eeb00a60 ..`. VMOV.F32 s0,s1
 0x000000e4: bd08 .. POP {r3,pc}
 0x000000e6: f7fffffe .... BL __mathlib_rredf2
 0x000000ea: e79a .. B {pc}-0xc8 ; 0x22
 0x000000ec: ee100a10 .... VMOV r0,s0
 0x000000f0: 0040 @. LSLS r0,r0,#1
 0x000000f2: f1b04f7f ...O CMP r0,#0xff000000
 0x000000f6: d3f3 .. BCC {pc}-0x16 ; 0xe0
 0x000000f8: d107 .. BNE {pc}+0x12 ; 0x10a
 0x000000fa: f04f0001 O... MOV r0,#1
 0x000000fe: f7fffffe .... BL __set_errno
 0x00000102: e8bd4008 ...@ POP {r3,lr}
 0x00000106: f7ffbffe .... B.W __mathlib_flt_invalid
 0x0000010a: e8bd4008 ...@ POP {r3,lr}
 0x0000010e: f7ffbffe .... B.W __mathlib_flt_infnan
 $d
 0x00000112: 0000 .. DCW 0
 0x00000114: 7e921fb6 ...~ DCD 2123505590
 0x00000118: 3f800000 ...? DCD 1065353216
 0x0000011c: 394c6d33 3mL9 DCD 961310003
 0x00000120: 3c0882da ...< DCD 1007190746
 0x00000124: be2aaaa0 ..*. DCD 3190467232
 0x00000128: 46490e49 I.IF DCD 1179192905
 0x0000012c: 3f22f983 .."? DCD 1059256707
 0x00000130: 4b000000 ...K DCD 1258291200
 0x00000134: 3fc90000 ...? DCD 1070137344
 0x00000138: 39fda000 ...9 DCD 972922880
 0x0000013c: 33a22000 . .3 DCD 866263040
 0x00000140: 2c34611a .a4, DCD 741630234
 0x00000144: bab23ab9 .:.. DCD 3132242617
 0x00000148: 3d2a9fca ..*= DCD 1026203594
 0x0000014c: beffffdd .... DCD 3204448221