On Wednesday, 1 June 2016 at 23:35:40 UTC, Era Scarecrow wrote:
On Wednesday, 1 June 2016 at 23:23:49 UTC, ZILtoid1991 wrote:
After some debugging, I found out that the p pointer becomes
null at the end instead of pointing to a value. I have no
experience with using in-line assemblers (although I made a
few Hello World programs for MS-Dos with a stand-alone
assembler), so I don't know when and how the compiler will
interpret the types from D.
In the assembler the variable names actually become just the
offset to where they are in the stack in relation to BP. So if
you want the full pointer you actually need to convert it into
a register first and then just use that register instead.
So.... This should be correct.
//unless you are going to actually use ubyte[4] here, just
making a pointer will work instead, so cast(uint*) probably
ubyte[4] src = *cast(ubyte[4]*)(palette.ptr + 4 * *c);
ubyte[4] *p = cast(ubyte[4]*)(workpad + (offsetX + x)*4 +
offsetY);
asm{ //moving the values to their destinations
movd ESI, src[EBP]; //get source pointer
movd EDI, p[EBP]; //get destination pointer
movd MM0, [EDI]; //use directly
movd MM1, [ESI];
movq MM5, alpha;
movq MM7, alphaMMXmul_const1;
movq MM6, alphaMMXmul_const2;
<snip>
movd [EDI], MM4;
}
I could get the code working with a bug after replacing pmulhuw
with pmullw, but due to integer overflow I get a glitched image.
I try to get around the fact that pmulhuw stores the high bits of
the result either with multiplication or with bit shifting.
