[Icc-mot] GNU to ICC

[Edward Karpicz]

Your GCC inline asm snippet doesn't look rocket science after scannig this:

http://www.ibiblio.org/gferg/ldp/GCC-Inline-Assembly-HOWTO.html


        int a=10, b;
        asm ("movl %1, %%eax;
              movl %%eax, %0;"
             :"=r"(b)        /* output */
             :"r"(a)         /* input */
             :"%eax"         /* clobbered register */
             );

Reformatting your code to have ':' in the right position makes it readable

__asm__ __volatile__ ("emul\n"
    "ldx #100\n"
    "ediv\n"
    :"=y" (utmp1)
    :"y" (flash4.ReqFuel),"d" (utmp1)
    :"x");


output in Y is utmp1
inputs: flash4.ReqFuel in Y reg, utmp1 in D reg
clobbered: X reg

You are almost right, you just missed emul prior to LDX  #100.


In C your snippet should be something like this:
////start
unsigned short utmp1;
unsigned short flash4.ReqFuel;  // I don't know anything about flash4 struct

utmp1 = ((unsigned long)utmp1 * flash4.ReqFuel) / 100u;
////end


Regards
Edward

----- Original Message ----- 
From: "Oskar Atkinson" <oskar at atk-it.com>
To: "Discussion List for ICC08/11/12/16 users. You do NOT need to subscribe 
toicc-announce if you are a member of this." <icc-mot at imagecraft.com>
Sent: Thursday, September 20, 2007 6:58 PM
Subject: RE: [Icc-mot] GNU to ICC


still learning and well, now I am stuck with some inline assembler ...

in GCC it is:

__asm__ __volatile__ ("emul\n"
    "ldx #100\n"
    "ediv\n":
    "=y" (utmp1):
    "y" (flash4.ReqFuel),
    "d" (utmp1):
    "x");

the GCC syntax is asm( asm instuctions : output : input : clobbered 
registers );

I read above in terms of parameters as:

load the content of C variable flash4.ReqFuel into register y
load the content of C variable utmp1 into register edx
ldx #100
ediv
store the content of register y to the C variable utmp1
reg x content is not valid anymore

Thanks for any hints
Oskar



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