Absolute Val for Integers?
Posted: Sun Jan 20, 2019 11:23 am
I notice that ABS(number) is only for floating point is there such a function for integers?
CD
CD
Code: Select all
n.i = -1234567890
Debug Abs(n) ; Shows 1234567890.0
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Absolute Val for Integers?
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Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 11:28 am
It works fine with integers. I don't know what the manual is talking about.
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 11:39 am
Code: Select all
y = 100
z = 110564567689766987
x = y - z
Debug Abs(x)I got 110564567689766880.0
There does seem to be some loss! Plus it returns a float not an integer.
CD
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 11:43 am
Abs() isn't for Integers/Quads, you got problems with large integers.
You have to define your own procedure:
Code: Select all
Debug Abs(-100000000000000001)
Code: Select all
Procedure.q AbsI(Value.q)
If Value < 0
ProcedureReturn -Value
Else
ProcedureReturn Value
EndIf
EndProcedure
Debug AbsI(-100000000000000001)
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 11:44 am
You can of course do this:
Wouls be nice to have ABS() for integers though.
Code: Select all
y = -457
If y < 0
y = y - (2 * y)
EndIf
Debug y
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 12:08 pm
And why doesn't do Pb this by itself? Shouldn't be so complicated that Abs () automatically detects whether it is an integer or a float.STARGÅTE wrote: You have to define your own procedure:Code: Select all
Procedure.q AbsI(Value.q) If Value < 0 ProcedureReturn -Value Else ProcedureReturn Value EndIf EndProcedure Debug AbsI(-100000000000000001)
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 12:08 pm
The quickest way (edit : no good for negative... ) :
(added)
No better way than STARGÅTE in procedures and with native instructions.
Code: Select all
#iAbs = $7FFFFFFFFFFFFFFF
...
...
MyInteger & #iAbsNo better way than STARGÅTE in procedures and with native instructions.
Code: Select all
Procedure.Q qAbs(A.Q)
! Xor RAX, RAX
! Add RAX, [p.v_A] ; let's define A
! Ja l_cancelabs ; positive? yes : cancel
; else
! Xor RAX, 0xFFFFFFFFFFFFFFFF ; A ! (-1)
! Add RAX, 1 ; A + 1
cancelabs:
ProcedureReturn
EndProcedureRe: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 12:19 pm
Agreed, but at least you don't have to resort to the Windows API to fix this.Josh wrote:And why doesn't do Pb this by itself?
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 12:42 pm
PB's casting rules are a bit special sometimes. If you pass an expression with a division to Abs() then PB would have to decide on some rules if, or if not, an integer division is done and/or integer or float Abs() is to be called etc., at least i think it's something in that direction.Josh wrote:And why doesn't do Pb this by itself? Shouldn't be so complicated that Abs () automatically detects whether it is an integer or a float.
<edit>
But I think an AbsI() would be nice, along with a compiler error if an integer is passed to Abs().
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 1:21 pm
Does PB offer you the posibility to have one procedure parameter which can reperesent different types?Josh wrote:And why doesn't do Pb this by itself? Shouldn't be so complicated that Abs () automatically detects whether it is an integer or a float.
Even if you use a structure with Union, how can you decide if it is a float or an integer value?
It is not so easy as you think.
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 1:23 pm
I correct my super mistake above...
maybe write on wishlist to have a native AbsI().
maybe write on wishlist to have a native AbsI().
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 2:05 pm
There are already several threads here on the forum about Abs() for integers, including feature requests:Olliv wrote:maybe write on wishlist to have a native AbsI().
viewtopic.php?f=3&t=3170
viewtopic.php?f=3&t=14073
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 8:58 pm
@Little John
Yes ! Thank you, but these threads contain folkloric acid, plus ASM routine was absolutely false !!
Anyway, there are several reasons, not having added integer absolute function, because technically there are several ways to prepare the op, and branch (Jcc) using could be shared, what a native function prevents to do.
Yes ! Thank you, but these threads contain folkloric acid, plus ASM routine was absolutely false !!
Anyway, there are several reasons, not having added integer absolute function, because technically there are several ways to prepare the op, and branch (Jcc) using could be shared, what a native function prevents to do.
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 9:35 pm
Because you wrote
I just wanted to say that this has already been requested (at least) twice. That's all.Olliv wrote:maybe write on wishlist to have a native AbsI().
Re: Absolute Val for Integers?
Posted: Sun Jan 20, 2019 10:33 pm
You can use for Windows x64 the msvcrt.dll (PB use this DLL for many purposes):
Code: Select all
;Windows x64
If OpenLibrary(0, "msvcrt.dll")
Prototype.q Abs64(V1.q)
Prototype.l Abs32(V2.l)
Abs64.Abs64 = GetFunction(0, "_abs64")
Abs32.Abs32 = GetFunction(0, "labs")
CloseLibrary(0)
Else
;Error
EndIf
y1.q = 100
z1.q = 110564567689766987
x1.q = y1 - z1
Debug Abs64(x1)
y2.l = 100
z2.l = 110564567
x2.l = y2 - z2
Debug Abs32(x2)