Method and apparatus for use in the design and manufacture of integrated circuits
View Patent ↗A method and apparatus are provided for manufacturing integrated circuits performing invariant integer division x/d. A desired rounding mode is provided and an integer triple (a,b,k) for this rounding mode is derived. Furthermore, a set of conditions for the rounding mode is derived. An RTL representation is then derived using the integer triple. From this a hardware layout can be derived and an integrated circuit manufactured with the derived hardware layout. When the integer triple is derived a minimum value of k for the desired rounding mode and set of conditions is also derived.
1. A computer-implemented method for generating a representation of an integrated circuit for performing invariant integer division x/d, the method comprising:
receiving n, d, and a desired rounding mode as inputs to a parameter creator, wherein x is an n-bit number and d is an invariant integer constant;
deriving, by the parameter creator, an integer triple (a,b,k) comprising deriving a minimum value of k based on the desired rounding mode and a set of conditions, deriving a value for a from the value of k that results in the smallest constant multiplier, and deriving a value for b from values of k and a having the smallest Hamming weight, wherein Round(x/d)=(ax+b)/2 k ;
deriving, by an RTL (Register Transfer Level) generator, an RTL representation of the logical operation (ax+b)/2 k using the integer triple, the RTL representation defining the behavior of the integrated circuit; and
generating, by a synthesis tool, said representation of said integrated circuit from the RTL representation for manufacture of said integrated circuit.
2. The method according to claim 1 in which the rounding mode is round towards zero.
3. The method according to claim 1 in which the rounding mode is round to nearest.
4. The method according to claim 1 in which the rounding mode is faithful rounding.
5. The method according to claim 1 , in which the derived value of b has the smallest Hamming weight of the possible values of b satisfying Round(x/d)=(ax+b)/2 k .
6. The method for generating a representation of an integrated circuit according to claim 1 , further comprising manufacturing the integrated circuit from the hardware layout.
7. The method according to claim 1 , wherein said derivation of k is different for different rounding modes.
8. An apparatus configured to generate a representation of an integrated circuit for performing invariant integer division x/d, the apparatus comprising:
a parameter creator implemented in a processor and configured to:
receive n, d, and a desired rounding mode as inputs, wherein x is an n-bit number and d is an invariant integer constant, and
derive an integer triple (a,b,k) where k is derived to be a minimum value based on the desired rounding mode and a set of conditions, a value for a is derived from the value of k that results in the smallest constant multiplier, and a value for b is derived from values of k and a having the smallest Hamming weight, wherein Round(x/d)=(ax+b)/2 k ;
an RTL (Register Transfer Level) generator implemented in a processor and configured to derive an RTL representation of the logical operation (ax+b)/2 k using the integer triple, the RTL representation defining the behaviour of the integrated circuit; and
a synthesis tool configured to generate said representation of said integrated circuit from the RTL representation for manufacture of said integrated circuit.
9. The apparatus according to claim 8 , wherein the derived value for b has the smallest Hamming weight of the possible values of b satisfying Round(x/d)=(ax+b)/2 k .
10. The apparatus according to claim 8 , wherein the desired rounding mode is round towards zero.
11. The apparatus according to claim 8 , wherein the desired rounding mode is round to nearest.
12. The apparatus according to claim 8 , wherein the desired rounding mode is faithful rounding.
13. The apparatus according to claim 8 , wherein the parameter creator is further configured to derive k differently for different rounding modes.
14. A non-transitory computer readable medium having stored thereon computer executable instructions that when executed cause at least one processor to generate a representation of an integrated circuit for performing invariant integer division x/d, the instructions including instructions that cause a processor to:
receive n, d, and a desired rounding mode as inputs to a parameter creator, wherein x is an n-bit number and d is an invariant integer constant;
derive, by the parameter creator, an integer triple (a,b,k) comprising deriving a minimum value of k based on the desired rounding mode and a set of conditions, deriving a value for a from the value of k that results in the smallest constant multiplier, and deriving a value for b from values of k and a having the smallest Hamming weight, wherein Round(x/d)=(ax+b)/2 k ;
derive, by an RTL (Register Transfer Level) generator, an RTL representation of the logical operation (ax+b)/2 k using the integer triple, the RTL representation defining the behaviour of the integrated circuit; and
generating, by a synthesis tool, said representation of said integrated circuit from the RTL representation for manufacture of said integrated circuit.
15. The non-transitory computer readable medium according to claim 14 , wherein the rounding mode is round towards zero.
16. The non-transitory computer readable medium according to claim 14 , wherein the rounding mode is round to nearest.
17. The non-transitory computer readable medium according to claim 14 , wherein the rounding mode is faithful rounding.
18. The non-transitory computer readable medium according to claim 14 , in which the derived value of b having the smallest Hamming weight of the possible values of b satisfying Round(x/d)=(ax+b)/2 k .
19. The non-transitory computer readable medium according to claim 14 , wherein said derivation of k is different for different rounding modes.