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[BUG/PRB.] ADJUST THE PRECISION OF THE FLOATING-POINT NUMBERS FOR THE FLOOR() FUNCTION
January 2024
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CCB
1. BUG:
There is a test program:
*PROC testfloorfunction
SET DECIMALS TO 2
?FLOOR(4294967295/16777216) && Displays 256 if SET("DECIMALS")<=3
SET DECIMALS TO 10
?FLOOR(4294967295/16777216) && Displays 255 if SET("DECIMALS")>=4
RETURN
* END OF PROC TESTFLOORFUNCTION.
We think they will display 255, but:
?FLOOR(4294967295/16777216) && Displays 256 if SET("DECIMALS")<=3
2. CAUSE:
There are some BUGs in the following code.
3. RESOLUTION:
We can write some code to fix the BUG.
Label74aba1 ::
push ecx ;0x0074aba1 : 51
push ebx ;0x0074aba2 : 53
push esi ;0x0074aba3 : 56
push edi ;0x0074aba4 : 57
call Fun420d8c ;0x0074aba5 : e8e261cdff
mov ebx , eax ;0x0074abaa : 8bd8
push ebx ;0x0074abac : 53
lea edi , dword ptr [ esp + 16 ] ;0x0074abad : 8d7c2410
mov esi , ebx ;0x0074abb1 : 8bf3
call Fun420dd3 ;0x0074abb3 : e81b62cdff
test eax , eax ;0x0074abb8 : 85c0
jne Label74ac99 ;0x0074abba : 0f85d9000000
movzx eax ,byte ptr [ebx] ;0x0074abc0 : 0fb603
add eax , 0FFFFFFD0h ;0x0074abc3 : 83c0d0
cmp eax , 029h ;0x0074abc6 : 83f829
ja Label74ac5f ;0x0074abc9 : 0f8790000000
movzx eax ,byte ptr [ eax + offset Data74acb4 ] ;0x0074abcf : 0fb680b4ac7400
jmp dword ptr [ 4 * eax + offset DataPtr74aca0 ] ;0x0074abd6 : ff2485a0ac7400
Label74abdd ::
mov dword ptr [ ebx + 4 ] , 014h ;0x0074abdd : c7430414000000
jmp Label74ac87 ;0x0074abe4 : e99e000000
Label74abe9 ::
lea esi , dword ptr [ ebx + 24 ] ;0x0074abe9 : 8d7318
call Fun6daa65 ;0x0074abec : e874fef8ff
jmp Label74ac87 ;0x0074abf1 : e991000000
Label74abf6 ::
mov ecx , dword ptr [ ebx + 8 ] ;0x0074abf6 : 8b4b08
sub esp , 08h ;0x0074ac00 : 83ec08
;
; ---------------------------------------------------------------------------------------------------
; VFP 9.0 FIX - ADJUST THE PRECISION OF THE FLOATING-POINT NUMBERS FOR THE FLOOR() FUNCTION
; March 2023
; ---------------------------------------------------------------------------------------------------
; CCB
;
; Sometimes the FLOOR() function returns wrong result, for example,
; SET DECIMALS TO 2
; ?FLOOR(4294967295/16777216) && Displays 256 if SET("DECIMALS")<=3
; SET DECIMALS TO 10
; ?FLOOR(4294967295/16777216) && Displays 255 if SET("DECIMALS")>=4
;
; 2023/3/21, by ccb
;
cmp dword ptr vfpa_sys9146_data,00h
jne Label74abfd
cmp dword ptr vfpa_sys9126_data,00h
je Label74abfd
cmp ecx,0Fh
jge Label74abfd
fld qword ptr [ ebx + 16 ]
fld st(0)
fabs
fldlg2
fxch st(1)
fyl2x
fld st(0)
fistp dword ptr [ esp ]
mov edx,dword ptr [ esp ]
cmp edx,80000000h
je Label74abfb
and edx,80000000h
test edx,edx
jne Label74abfb
mov eax,0
IFDEF RAX
push esi
lea esi , dword ptr [ Data922438 ]
fadd qword ptr [ 8 * eax + esi ]
pop esi
ELSE
fadd qword ptr [ 8 * eax + offset Data922438 ]
ENDIF
mov eax,0Ah
IFDEF RAX
push esi
lea esi , dword ptr [ Data922438 ]
fadd qword ptr [ 8 * eax + esi ]
pop esi
ELSE
fadd qword ptr [ 8 * eax + offset Data922438 ]
ENDIF
fistp dword ptr [ esp ]
mov eax,0Fh
sub eax,dword ptr [ esp ]
cmp eax,0
jl Label74abfc
cmp eax,0Fh
jg Label74abfc
cmp eax,ecx
jle Label74abfc
fld st(0)
fistp dword ptr [ esp ]
mov edx,dword ptr [ esp ]
cmp edx,80000000h
je Label74abfc
and edx,80000000h
test edx,edx
jne Label74abfa
IFDEF RAX
push esi
lea esi , dword ptr [ Data922438 ]
fadd qword ptr [ 8 * eax + esi ]
pop esi
ELSE
fadd qword ptr [ 8 * eax + offset Data922438 ]
ENDIF
jmp Label74ac06
Label74abfa ::
IFDEF RAX
push esi
lea esi , dword ptr [ Data922438 ]
fadd qword ptr [ 8 * eax + esi ]
pop esi
ELSE
fadd qword ptr [ 8 * eax + offset Data922438 ]
ENDIF
jmp Label74ac06
Label74abfb ::
fstp st(0)
jmp Label74abfc
Label74abfc ::
fstp st(0)
jmp Label74abfd
Label74abfd ::
IFDEF RAX
push esi
lea esi , dword ptr [ Data922450 ]
fld qword ptr [ 8 * ecx + esi ] ;0x0074abf9 : dd04cd50249200
pop esi
ELSE
fld qword ptr [ 8 * ecx + offset Data922450 ] ;0x0074abf9 : dd04cd50249200
ENDIF
fadd qword ptr [ ebx + 16 ] ;0x0074ac03 : dc4310
Label74ac06 ::
fst qword ptr [ ebx + 16 ] ;0x0074ac06 : dd5310
fstp qword ptr [ esp ] ;0x0074ac09 : dd1c24
call floor ;0x0074ac0c : ff15a0799100
xor edx , edx ;0x0074ac12 : 33d2
fst qword ptr [ ebx + 16 ] ;0x0074ac14 : dd5310
mov dx , word ptr [ ebx + 22 ] ;0x0074ac17 : 668b5316
add esp , 08h ;0x0074ac1b : 83c408
shr edx , 04h ;0x0074ac1e : c1ea04
and edx , 07FFh ;0x0074ac21 : 81e2ff070000
sub edx , 03FFh ;0x0074ac27 : 81eaff030000
cmp edx , 01Fh ;0x0074ac2d : 83fa1f
jnl Label74ac4d ;0x0074ac30 : 7d1b
call Fun4337e6 ;0x0074ac32 : e8af8bceff
mov dword ptr [ ebx + 12 ] , eax ;0x0074ac37 : 89430c
mov byte ptr [ebx] , 049h ;0x0074ac3a : c60349
mov dword ptr [ ebx + 4 ] , 014h ;0x0074ac3d : c7430414000000
mov dword ptr [ ebx + 8 ] , 00h ;0x0074ac44 : c7430800000000
jmp Label74ac87 ;0x0074ac4b : eb3a
Label74ac4d ::
fstp st(0) ;0x0074ac4d : ddd8
mov dword ptr [ ebx + 4 ] , 014h ;0x0074ac4f : c7430414000000
mov dword ptr [ ebx + 8 ] , 00h ;0x0074ac56 : c7430800000000
jmp Label74ac87 ;0x0074ac5d : eb28
Label74ac5f ::
test byte ptr [ Data936f10 ] , 01h ;0x0074ac5f : f605106f930001
je Label74ac7d ;0x0074ac66 : 7415
mov eax , dword ptr [ Data936f14 ] ;0x0074ac68 : a1146f9300
test eax , eax ;0x0074ac6d : 85c0
jne Label74ac87 ;0x0074ac6f : 7516
mov dword ptr [ Data936f14 ] , 0385h ;0x0074ac71 : c705146f930085030000
jmp Label74ac87 ;0x0074ac7b : eb0a
Label74ac7d ::
mov ecx , 0385h ;0x0074ac7d : b985030000
call Fun544742 ;0x0074ac82 : e8bb9adfff
Label74ac87 ::
mov eax , dword ptr [ esp + 12 ] ;0x0074ac87 : 8b44240c
test eax , eax ;0x0074ac8b : 85c0
je Label74ac99 ;0x0074ac8d : 740a
mov byte ptr [ebx] , 030h ;0x0074ac8f : c60330
mov dword ptr [ ebx + 12 ] , 049h ;0x0074ac92 : c7430c49000000
Label74ac99 ::
pop edi ;0x0074ac99 : 5f
pop esi ;0x0074ac9a : 5e
pop ebx ;0x0074ac9b : 5b
pop ecx ;0x0074ac9c : 59
ret ;0x0074ac9d : c3
4. APPLIES TO:
VFP 6.0.8167.0
VFP 6.0.8961.0 (SP5)
VFP 7.0.0.9262
VFP 7.0.0.9465 (SP1)
VFP 8.0.0.2521
VFP 8.0.0.3117 (SP1)
VFP 9.0.0.2412
VFP 9.0.0.3504 (SP1)
VFP 9.0.0.4611 (SP2)
VFP 9.0.0.5015 (SP2)
VFP 9.0.0.5411 (SP2)
VFP 9.0.0.5721 (SP2)
VFP 9.0.0.5815 (SP2)
VFP 9.0.0.6303 (SP2)
VFP 9.0.0.6602 (SP2)
VFP 9.0.0.7423 (SP2)
The bug has been fixed in VFP Advanced.
5. REFERENCE WEBSITES:
1, baiyujia.com:
http://www.baiyujia.com
http://www.baiyujia.com/vfpdocuments/f_vfp9fix257.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix23.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix24.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix37.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix38.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix97.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix98.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix123.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix124.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix255.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix256.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix259.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix260.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix303.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix304.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix305.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix306.asp
2, foxite.com:
https://www.foxite.com/archives/binary-to-hex-0000494011.htm
6. OTHER:
For reference only, there is no guarantees.
Any questions or suggestions, please send me an email at ccb2000@163.com.
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