assembly conversions

[Brian Alvarez]

Thanks Charles, ill give it another go this afternoon.

[Charles Pegge]

mods in Tokenize:

at the start:

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'    ASCIIZ PTR addrptr
'    @addrptr = (STRPTR(sourceinput))
sys addrptr=STRPTR(sourceinput)
    push ebx
    mov edi, w
    mov esi, addrptr

at the end:

Code: [Select]

storekeyword:
    inc edi
    mov a, esi
    mov c, cl
    mov l, edx
    mov w, edi
    mov k, ah
pop ebx
mbox "ok1"
    ¤UDT_SETV(dictionary, dictionary.m(w), (0), DWORD, (a), 4)
    ¤UDT_SETV(dictionary, dictionary.m(w), (4), INTEGER, (l), 2)
    ¤UDT_SETV(dictionary, dictionary.m(w), (6), BYTE, ¤BytOvf(k), 1)
    ¤PRINTSTR("=================", 1)
    ¤PRINTSTR(STR$(w, null), 1)
    ¤PRINTSTR(STR$(a, null), 1)
    ¤PRINTSTR(STR$(c, null), 1)
    ¤PRINTSTR(STR$(l, null), 1)
    ¤PRINTSTR(STR$(k, null), 1)
'    jmp checknext
'can't get here with that jump
mbox "ok2"
    RETURN ¤RETVAL
END FUNCTION


[Brian Alvarez]

 Ok i think i got the conversions working. I now need to convert the behavior of MOV for BASIC. It makes no sense, i think the guides are oudated...

 In some flavors MOV passes the variable byval and in order to pass its address to a register it requires LEA...  in such cases INC increases its value and you can move the value back to a variable using MOV back. Makes sense.

 In some other codes, using MOV pasess the address of the variable to a register, and using INC increases the address. It  requires a special syntax to increase its value (INC with the address directly does nothing) and LEA is not required... This also makes sense but i dont know what guide to follow.

[Brian Alvarez]

 Yup. The sample tokenizer now compiles fine for PowerBASIC and Oxygen without tweakings required. Ill try some benchmarks later.

[Charles Pegge]

A typical direct local variable might be [ebp-108] and lea (load effective address) would resolve its absolute address by subtracting 108 from the ebp value, and storing this value in the target register.

lea ecx,[ebp-108]

you could now use [ecx] to access the variable.

mov eax,[ecx]
...
inc ecx 'next byte

[Brian Alvarez]

 Thanks Charles, I think I have implemented that and few other tricks. However i have a question. I can do,

Code: [Select]

mov ebx, dwordvar
 I can also do:

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mov ch, [esi]
and:

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mov ch, 64
 But i am having problems doing:

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mov ch, bytevar
 How can i pass a byte value from a byte variable into the subregister ch and the other 8 bit ones? I imagine i can create a copy into another register, but is there a more direct way without creating a copy?

[Brian Alvarez]

 Basically i am doing this (see image attached).

 I am backing up and restoring registers correctly between ASM/BASIC code.

 s is a byte variable.

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mov ch, s
 But it doesnt seem to work.

 The whole rest works marvelously!

[Charles Pegge]

How have you defined s. Is it a direct integer or byte?

[Brian Alvarez]

It is defined as:

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byte s

[Charles Pegge]

is s local? If not, assign to a local byte.

[Brian Alvarez]

Got it. It worked.

[JRS]

Watching you guys work together is better than going to the movies. 

[Brian Alvarez]

 PowerBASIC's TIMER function displays slightly different measurements, but so far Oxygen is leading the benchmarks. 

 Hopefully this keeps like this when i fiish debugging completely the conversions and i test using GetTickCount(). 

[JRS]

It would be interesting to see how FreeBasic compares between PB and O2.

Would BCX be a good reference to use as a C translated BASIC?

[Charles Pegge]

In FreeBasic, Assembler blocks require asm .. end asm, and the variable names are contained within square brackets.

thus:

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dim as long a
asm
  mov eax,[a]
  inc eax
  mov [a],eax
end asm
...
[code]