Pure FB Runtime Library (in progress)

[Josep Roca]

> I get what it is supposed to do, but why would you choose that over a multi-line comment? Is there some benefit that I don't know about?

Maybe multi-line comments were not yet implemented when that code was written. Anyway, a comment is a comment, isn't it?

[Imortis]

> I get what it is supposed to do, but why would you choose that over a multi-line comment? Is there some benefit that I don't know about?

Maybe multi-line comments were not yet implemented when that code was written. Anyway, a comment is a comment, isn't it?

It is in C code so it was implemented. I just didn't know if there was some benefit to using it that I was unaware of. One I can see is syntax highlighting still happens in the IDE. That could be it. I only ask because I am converting the code and was changing them to multi-line comments at first, but now I am leaving them because of the syntax highlighter.

[caseih]

In C you can't nest multi line comments so if you want to comment out a complete section of code that might contain multi line comments, this ifdef idiom is often used.

[Imortis]

In C you can't nest multi line comments so if you want to comment out a complete section of code that might contain multi line comments, this ifdef idiom is often used.

Ah ha! That makes sense. Thanks for the explanation. I used C in college and not much outside of that, so a lot of this is stuff I have never seen before.

[Imortis]

To anyone who wants to try:

I have converted all of the standard FB String methods. I am not sure if they are correct. If someone would like to try and test the code, or tell me how I can test it (it throws errors because of the missing WString functions), I would be all ears for fixes/advice.

[Josep Roca]

A function like this

Code: Select all

function fb_CHR cdecl ( args as long, ... ) as FBSTRING ptr

won't work with FB 64-bit, that does not support variadic functions.

It is going to be a 32-bit only runtime?

[Imortis]

That is the way it was written in C, so that is what I have translated. I hope that the bug in the C emitter will be fixed to allow this to work in any bit depth.

[TeeEmCee]

OK, I got it to compile and run on linux-x86 after fixing some bugs. Should work on win32 too, if you have the prereqs for compiling libfb itself there (I don't, but aside from that, crosscompiling seemed to work). I copied out some parts of FB's makefile and modified it to prefer .bas files over .c files. It proved quite painful; I hate writing makefiles. Made a pull request

A test:

dim as string a = "hello!", b
b = "a23"
? a
? str(32)
? a+b
? string(10, "a")
? chr(65,66,67,68)
? left(a,3), right(a,3)
? ucase(a)

Output:

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hello!
32
hello!a23
aaaaaaaaaa
ABCD
hel           lo!
fish: Job 2, “./hello” terminated by signal SIGSEGV (Address boundary error)

I noticed a problem: TRUE is defined as 1, which is the value used in C, but FB uses -1. However, if you change TRUE to -1, then there will probably be some incompatibilities between modules written in C and those in FB. Also, over the place you've translated !X to not(X), but that works only if X takes only the values 0 and -1.
I think TRUE should almost certainly be changed to -1, never mind compatibility of internal structs. However this does mean you need to be careful anywhere that truth values are used, whether replacing 1 with -1 and ! with not changes the logic (not just where TRUE is used, but also for any logical operators)

[fxm]

Code: Select all

Dim As Boolean b = True

Print Cast(Byte, b)
Print Hex(Cast(Byte, b), 2)

Sleep

-1
FF

[Imortis]

OK, I got it to compile and run on ... Made a pull request

Thank you so much! I have merged your changes. Anyone else who wants to contribute is welcome to do so. Find bugs I missed! After I finish the array functions, I am going to work on getting all of the OS specific files translated, so I will need non windows people to test that bit for me.

Also, @TeeEmCee: can I get you to send me a copy of that make file? It would help me out quite a bit.

[TeeEmCee]

Damnit, I forgot to actually add the makefile to git! Sorry about about; I made another pull req for it.
There's a lot of stuff in FB's makefile that I left out, in particular most OS-specific stuff, including support for building for DOS. It can be added back later. But I guess actually targetting DOS is something that fbrtLib could excel at. Anyway, at 300+ lines, almost nothing in this makefile is actually necessary, but I thought it would be good to stay close to FB's own build system.

[fatman2021]

I have run into a snag using your version of the runtime:

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#include "LibFB/fb.bi"
#include "LibFB/str_chr.bas"
#include "LibFB/str_core.bas"

DECLARE SUB PrintString(src AS Byte Ptr, x AS LONG, y AS LONG)
DECLARE SUB main ()
 
SUB multiboot ()
   Asm
 
     'setting up the Multiboot header - see GRUB docs for details
 
     .set ALIGN,    1<<0             
     .set MEMINFO,  1<<1             
     .set FLAGS,    ALIGN | MEMINFO  
     .set MAGIC,    0x1BADB002       
     .set CHECKSUM, -(MAGIC + FLAGS) 
 
     .align 4
     .LONG MAGIC
     .LONG FLAGS
     .LONG CHECKSUM
 
     .set STACKSIZE, 0x4000          
     .comm stack, STACKSIZE, 32      

     .global loader                  
 
     loader:
       lea   esp, stack + STACKSIZE
       push  eax                       
       push  ebx                       
 
       CALL  MAIN
 
       cli
       hlt                    
   END Asm
 
END SUB
 
SUB main ()

    ' ONST s = fb_CHR(97)
    PrintString CPtr(Byte Ptr, @Chr(97)), 35, 12
 
END SUB
 
SUB PrintString(src AS Byte Ptr, x AS LONG, y AS LONG)
 
    DIM dst AS Byte Ptr
    DIM counter AS LONG
 
    dst = CPtr(Byte Ptr, &HB8000 + y * 160 + x * 2)
 
    counter = 0
 
    WHILE src[counter] <> 0
        dst[2 * counter] = src[counter]
        dst[2 * counter + 1] = 15
        counter = counter + 1
    WEND
END SUB

[main@Manjaro FBCDOS]$ ld -m elf_i386 -T link.ld -o kernel.bin kernel.o
kernel.o: In function `fb_CHR':
(.text+0x32): undefined reference to `__fb_ctx'
(.text+0x9c): undefined reference to `__fb_ctx'
kernel.o: In function `fb_hStrAllocTmpDesc':
(.text+0x107): undefined reference to `fb_hListInit'
(.text+0x114): undefined reference to `fb_hListAllocElem'
kernel.o: In function `fb_hStrFreeTmpDesc':
(.text+0x170): undefined reference to `fb_hListFreeElem'
kernel.o: In function `fb_hStrAlloc':
(.text+0x222): undefined reference to `malloc'
(.text+0x23e): undefined reference to `malloc'
kernel.o: In function `fb_hStrRealloc':
(.text+0x314): undefined reference to `fb_StrDelete'
(.text+0x323): undefined reference to `malloc'
(.text+0x33f): undefined reference to `malloc'
(.text+0x366): undefined reference to `realloc'
(.text+0x385): undefined reference to `realloc'
kernel.o: In function `fb_hStrDelTemp_NoLock':
(.text+0x4f1): undefined reference to `fb_StrDelete'
kernel.o: In function `FB_MEMCPYX':
(.text+0x667): undefined reference to `memcpy'

[TeeEmCee]

Sorry, you can't simply include a couple source files from the library and expect it to work. Those files have dependencies on many other files, and on libc, as you noticed.
Quite a lot of the minimum code that needs to be linked is related to initialising the console, actually, so that PRINT can work.
In your case, running without an OS, I guess the DOS console backend code might work, if it accessed video memory or BIOS directly instead of using DOS interrupts to print? (I don't know)

Somebody wrote an OS in FreeBasic, have a look into what they did.

[fatman2021]

malloc, realloc, memcpy, etc should be easy to implement in FreeBASIC as the C versions the functions are really not all that complicated. What I need to know is the names of the files that contain various functions such as __fb_ct, fb_hListInit, fb_hListAllocElem, fb_StrDelete, etc.

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function memcpy(dest as byte ptr, src as byte ptr, n as long)
 '' Typecast src and dest addresses to (char *)
 dim  as byte ptr csrc = (byte ptr)src
 dim  as byte ptr cdest = (byte ptr)dest

 '' Copy contents of src[] to dest[]
 dim as integer i
 for i = 0 to n
  cdest[i] = csrc[i]
 next i
end function

[TeeEmCee]

There are several mistakes in your memcpy.

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> grep "dim.*__fb_ctx" *.bas
init.bas:dim __fb_ctx as FB_RTLIB_CTX
str_format.bas:    dim as FBSTRING ptr dst = @__fb_ctx.null_desc

Other functions like fb_hListInit don't exist (grep fb_hListInit *.bas). That's because fbrtLib is mostly incomplete. You still need to use (at least parts of) FB's official rtlib.