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[BUG/PRB.] ADJUST THE PRECISION OF THE FLOATING-POINT NUMBERS FOR THE INT() FUNCTION
January 2024
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CCB
1. BUG:
There is a test program:
*PROC testintfunction
SET DECIMALS TO 2
?INT(4294967295/16777216) && Displays 256 if SET("DECIMALS")<=3
SET DECIMALS TO 10
?INT(4294967295/16777216) && Displays 255 if SET("DECIMALS")>=4
RETURN
* END OF PROC TESTINTFUNCTION.
We think they will display 255, but:
?INT(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.
Label4d9d4e ::
push ebp ;0x004d9d4e : 55
mov ebp , esp ;0x004d9d4f : 8bec
and esp , 0FFFFFFF8h ;0x004d9d51 : 83e4f8
push ecx ;0x004d9d54 : 51
push ebx ;0x004d9d55 : 53
push esi ;0x004d9d56 : 56
push edi ;0x004d9d57 : 57
call Fun420d8c ;0x004d9d58 : e82f70f4ff
mov ebx , eax ;0x004d9d5d : 8bd8
push ebx ;0x004d9d5f : 53
lea edi , dword ptr [ esp + 16 ] ;0x004d9d60 : 8d7c2410
mov esi , ebx ;0x004d9d64 : 8bf3
call Fun420dd3 ;0x004d9d66 : e86870f4ff
test eax , eax ;0x004d9d6b : 85c0
jne Label4d9df4 ;0x004d9d6d : 0f8581000000
mov al , byte ptr [ebx] ;0x004d9d73 : 8a03
cmp al , 049h ;0x004d9d75 : 3c49
je Label4d9de8 ;0x004d9d77 : 746f
cmp al , 04Eh ;0x004d9d79 : 3c4e
jne Label591c3a ;0x004d9d7b : 0f85b97e0b00
fld qword ptr [ ebx + 16 ] ;0x004d9d81 : dd4310
mov ecx , dword ptr [ ebx + 8 ] ;0x004d9d84 : 8b4b08
fcomp qword ptr [ Data91fbc8 ] ;0x004d9d87 : dc1dc8fb9100
lea esi , dword ptr [ ebx + 16 ] ;0x004d9d8d : 8d7310
fld qword ptr [esi] ;0x004d9d90 : dd06
add ecx , 03h ;0x004d9d92 : 83c103
fstsw ax ;0x004d9d95 : dfe0
test byte ptr ah , 05h ;0x004d9d97 : f6c405
jnp Label591c7a ;0x004d9d9a : 0f8bda7e0b00
fcomp qword ptr [ Data91fbc8 ] ;0x004d9da0 : dc1dc8fb9100
fstsw ax ;0x004d9da6 : dfe0
test byte ptr ah , 041h ;0x004d9da8 : f6c441
jne Label4d9db8 ;0x004d9dab : 750b
;
; -------------------------------------------------------------------------------------------------
; VFP 9.0 FIX - ADJUST THE PRECISION OF THE FLOATING-POINT NUMBERS FOR THE INT() FUNCTION
; March 2023
; -------------------------------------------------------------------------------------------------
; CCB
;
; Sometimes the INT() function returns wrong result, for example,
; SET DECIMALS TO 2
; ?INT(4294967295/16777216) && Displays 256 if SET("DECIMALS")<=3
; SET DECIMALS TO 10
; ?INT(4294967295/16777216) && Displays 255 if SET("DECIMALS")>=4
;
; 2023/3/21, by ccb
;
cmp dword ptr vfpa_sys9146_data,00h
jne Label4d9db1
cmp dword ptr vfpa_sys9125_data,00h
je Label4d9db1
cmp ecx,0Fh
jge Label4d9db1
sub esp , 08h
fld qword ptr [esi]
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 Label4d9daf
and edx,80000000h
test edx,edx
jne Label4d9daf
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 Label4d9db0
cmp eax,0Fh
jg Label4d9db0
cmp eax,ecx
jle Label4d9db0
fld st(0)
fistp dword ptr [ esp ]
mov edx,dword ptr [ esp ]
cmp edx,80000000h
je Label4d9db0
and edx,80000000h
test edx,edx
jne Label4d9dae
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
add esp , 08h
jmp Label4d9db6
Label4d9dae ::
IFDEF RAX
push esi
lea esi , dword ptr [ Data922438 ]
fsub qword ptr [ 8 * eax + esi ]
pop esi
ELSE
fsub qword ptr [ 8 * eax + offset Data922438 ]
ENDIF
add esp , 08h
jmp Label4d9db6
Label4d9daf ::
fstp st(0)
jmp Label4d9db0
Label4d9db0 ::
fstp st(0)
add esp , 08h
jmp Label4d9db1
Label4d9db1 ::
IFDEF RAX
push esi
lea esi , dword ptr [ Data922438 ]
fld qword ptr [ 8 * ecx + esi ] ;0x004d9dad : dd04cd38249200
pop esi
ELSE
fld qword ptr [ 8 * ecx + offset Data922438 ] ;0x004d9dad : dd04cd38249200
ENDIF
fadd qword ptr [esi] ;0x004d9db4 : dc06
Label4d9db6 ::
fstp qword ptr [esi] ;0x004d9db6 : dd1e
Label4d9db8 ::
xor eax , eax ;0x004d9db8 : 33c0
mov ax , word ptr [ ebx + 22 ] ;0x004d9dba : 668b4316
shr eax , 04h ;0x004d9dbe : c1e804
and eax , 07FFh ;0x004d9dc1 : 25ff070000
sub eax , 03FFh ;0x004d9dc6 : 2dff030000
cmp eax , 01Fh ;0x004d9dcb : 83f81f
jnl Label591c86 ;0x004d9dce : 0f8db27e0b00
fld qword ptr [esi] ;0x004d9dd4 : dd06
call Fun4337e6 ;0x004d9dd6 : e80b9af5ff
mov dword ptr [ ebx + 12 ] , eax ;0x004d9ddb : 89430c
mov byte ptr [ebx] , 049h ;0x004d9dde : c60349
Label4d9de1 ::
mov dword ptr [ ebx + 8 ] , 00h ;0x004d9de1 : c7430800000000
Label4d9de8 ::
mov eax , dword ptr [ esp + 12 ] ;0x004d9de8 : 8b44240c
test eax , eax ;0x004d9dec : 85c0
jne Label591cb1 ;0x004d9dee : 0f85bd7e0b00
Label4d9df4 ::
pop edi ;0x004d9df4 : 5f
pop esi ;0x004d9df5 : 5e
pop ebx ;0x004d9df6 : 5b
mov esp , ebp ;0x004d9df7 : 8be5
pop ebp ;0x004d9df9 : 5d
ret ;0x004d9dfa : 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_vfp9fix255.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix23.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix24.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_vfp9fix257.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix258.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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