Re: Doubt in memcpy() and memset()

Tom St Denis wrote:

Kenneth Brody wrote:
No, but if you are passing an int rather than unsigned char, it
may need to zero-fill the rest of the int before passing it.

unsigned char x;
int ix;

x = 4;
ix = x;

What am I missing?

totally legal conversion provided you keep the values in x to the
portable range.

I may be mistaken here, but...

extern void foo(unsigned char c);
extern void bar(int i);

void foobar()
{
unsigned char c = 'x';

foo(c);
bar(c);
}

Here, the call to foo() can push the single byte of c (if the system
allows one to push a byte), or load the byte into a register and then
push the register. However, the call to bar() requires that the byte
be loaded into a register, while zero-filling the register prior to
pushing it on the stack.

Perhaps something like:

load al,[c]
push eax
call foo

xor eax,eax
load al,[c]
push eax
call bar

(Yes, this example assumes the concept of registers and a stack.)

--
+-------------------------+--------------------+-----------------------+
| Kenneth J. Brody | www.hvcomputer.com | #include |
| kenbrody/at\spamcop.net | www.fptech.com | <std_disclaimer.h> |
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.

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