What's wrong with this NV_fragment_program2?

[FMS]

Hi,

I am writing this shader and I don't seem to follow why "SUBR" is not providing me the correct results. I checked the contents of the variables and they seems to be fine. Apparently when I try to do the subtraction between "Coordinates" and "Position", the "COLOR" results in some junk values.

Here is the source code:
#################################################
"!!ARBfp1.0\n"

"OPTION NV_fragment_program2;\n"

"ATTRIB ParticleIndex = fragment.texcoord[2];\n"

"OUTPUT COLOR = result.color;\n"

"PARAM Root = {0.0, 0.0};\n"
"PARAM Width = program.env[0]; # width is 4\n"

"TEMP MassAddress;\n"
"TEMP Position;\n"
"TEMP Coordinates;\n"
"TEMP GridIndex;\n"
"TEMP Index;\n"
"TEMP fraction;\n"
"TEMP temp;\n"

"TEX Coordinates, ParticleIndex, texture[2], RECT;\n"

"TEX MassAddress, Root, texture[0], RECT;\n"
"MOVR Index.x, MassAddress.z;\n"
"CAL DECODEINDEX;\n"

"TEX MassAddress, GridIndex, texture[0], RECT;\n"
"TEX Position, GridIndex, texture[1], RECT;\n"
"SUBR COLOR, Coordinates, Position;\n"
"RET;\n"

"DECODEINDEX:\n"
"DIVR GridIndex.y, Index.x, Width.x;\n"
"FRCR fraction.x, GridIndex.y;\n"
"MULR GridIndex.x, fraction.x, Width.x;\n"
"RET;\n"

"END\n";
#################################################

Please help.

Platform : x86(AMD) , Linux RedHat 9.0
Graphics Hardware : GeForce 6600 GT

Thanks.
- FMS

[def]

SUB is not a hardware funtion, it is substituted with an ADD. Have you tried this:

"ADDR COLOR, Coordinates, -Position;\n"

Maybe its a bug in the driver...