In order to effectively reduce branch hazards without a restriction to a structure of a pipeline, the contents of instructions and the like during control of conditional branching in an information processing apparatus which processes an instruction by pipeline processing, before a condition of a conditional branch instruction becomes defined, that is, before a branch judgement is made, pipeline information of a subsequent instruction which is subsequent to the conditional branch instruction is saved so that an instruction beyond a branch is fed to a pipeline in advance. When the condition is met, the instruction beyond the branch is executed as it directly is. When the condition is not met, the saved pipeline information of the subsequent instruction is returned to the pipeline and the subsequent instruction which is subsequent to the conditional branch instruction is executed.
An apparatus to perform no-latency conditional branching has a sequencer for executing program instructions including one or more conditional branch instructions. The conditional branch instruction is a binary word specifying a branch condition address and a conditional instruction. The branch unit has a programmable flag selection memory and a plurality of first flag selectors and determines in hardware whether to branch according to the conditional instruction. Each first flag selector accepts a plurality of available flags and selects a flag based upon contents in the flag selection memory. A second flag selector accepts the flags from the first flag selectors and selects one of the flags to present as a branch flag based upon the branch condition address. The branch flag indicates whether to branch to the destination address.
Method in a pipeline processing stage in a processor, includes the steps of: receiving a first block from a first register and a first execution parameter associated with the first block from a second register, the execution parameter having a first value; inspecting a set of data being at least a part of the first block; and, if the set of data differs from a predetermined condition, storing a second execution parameter on a third register and a third execution parameter on the second register, where the second execution parameter has a second value and is associated with the first block and the third execution parameter has the first value and will be associated with a second block. The invention also relates to the pipeline processor, a module, an integrated circuit and a computer unit.
A method for synchronizing divergent samples in a programmable graphics processing unit is described. In one embodiment, the method includes the steps of determining that a divergence has occurred and detecting that a first sample of a group of samples has encountered a first synch token. The method also includes the steps of determining whether each of the other samples of the group has encountered a synch token and determining whether the synch token encountered by each of the other samples of the group is the first synch token.
A method for processing divergent samples in a programmable graphics processing unit is described. In one embodiment, the method includes the step of incrementing a subroutine depth of a first sample to designate that first call instructions are to be executed on the first sample. The method also includes the steps of pushing state data of a second sample upon which the first call instructions are not to be executed onto a global stack and executing the first call instructions on the first sample.
