Re: [PATCH] kvm: testsuite: Add test for 'call near absolute'

[Avi Kivity <avi@qumranet.com>]

Mohammed Gamal wrote:
> Add test for 'call near abolsute' instruction to the real mode test harness
>
>  
> +void test_call(struct regs *inregs, struct regs *outregs)
> +{
> +	MK_INSN(call1, "mov $0x4000, %eax \n\t"
> +		       "call *%eax\n\t");
> +
> +	exec_in_big_real_mode(inregs, outregs,
> +		   	      insn_call1,
> +			      insn_call1_end - insn_call1);
>   

Please test registers for damage (using regs_equal).

> +}
> +
> +void line_out()
> +{	
> +	/* Just output a blank line */
> +	asm(".org 0x4000 \n\t"
> +	    "mov $10, %al \n\t"
> +	    "out %al, $0xf1 \n\t");
> +}
>   

When the code grows and occupies address 0x4000, this will break.

I suggest:

void test_function(void);
asm ("test_function: mov $1234, %eax; ret");

This sets up a register to see that the call actually did something, and 
avoids the gcc function prologue/epilogue which may clobber registers.



-- 
error compiling committee.c: too many arguments to function