Performing comparison operations using vector floating point values

A ray tracing unit configured to perform an intersection testing process, the ray tracing unit being configured to perform a particular comparison operation using floating point values as part of the intersection testing process, the ray tracing unit being configured to:

• receive the floating point values in a scalar format;
• promote the received floating point values to a vector format, wherein the received floating point values are used as a first component of the vector floating point values;
• set a second component of one or more of the vector floating point values to a non-zero, finite value;
• perform the particular comparison operation using the vector floating point values to determine a vector result having first and second components;
• determine a scalar result of the particular comparison operation, wherein the magnitude of the scalar result is given by the magnitude of the first component of the vector result, and wherein:
• if the first component of the vector result is non-zero then the sign of the scalar result equals the sign of the first component of the vector result, and
• if the first component of the vector result is zero and if the second component of the vector result is non-zero then the sign of the scalar result equals the sign of the second component of the vector result;
• and
• output the scalar result of the particular comparison operation, wherein the outputted result of the particular comparison operation is used in the ray tracing unit to render an image.

A non-transitory computer readable storage medium having stored thereon an integrated circuit definition dataset that, when processed in an integrated circuit manufacturing system, configures the integrated circuit manufacturing system to manufacture a ray tracing unit configured to perform an intersection testing process, the ray tracing unit being configured to perform a particular comparison operation using floating point values as part of the intersection testing process, the ray tracing unit being further configured to:

• receive floating point values in a scalar format;
• promote the received floating point values to a vector format, wherein the received floating point values are used as a first component of the vector floating point values;
• set a second component of one or more of the vector floating point values to a non-zero, finite value;
• perform the particular comparison operation using the vector floating point values to determine a vector result having first and second components;
• determine a scalar result of the particular comparison operation, wherein the magnitude of the scalar result is given by the magnitude of the first component of the vector result, and wherein:
• if the first component of the vector result is non-zero then the sign of the scalar result equals the sign of the first component of the vector result, and
• if the first component of the vector result is zero and if the second component of the vector result is non-zero then the sign of the scalar result equals the sign of the second component of the vector result;
• and
• output the scalar result of the particular comparison operation, wherein the outputted result of the particular comparison operation is used in the ray tracing unit to render an image.