The control APIs

Time control

void srl_sleep_cycles(int n)

Waits at least n cycles pass. Calling task may be unscheduled meanwhile.

Parameters:

• n – Number of cycles

void srl_busy_cycles(int n)

Waits n cycles pass in the hardware.

Parameters:

• n – Number of cycles

When using a software implementation of a task for hardware coprocessor evaluation, some timing accuracy tweaks may be useful.

Purpose of this call is to simulate the latency of an hardware coprocessor latency from the software task’s code. When running as a SyntheticTask, all computation is done with no latency.

Condition waiting API

Sometimes, tasks have to poll from an hardware register until it has some defined condition satisfied. Here are some calls to implement such polling. When using these calls, tasks may be unscheduled until the condition is satisfied.

void srl_sched_wait_COMP_ENDIANNESS(uint32_t *addr, int32_t val)

This function exists with different values of COMP and ENDIANNESS.

COMP is in eq (==), ne (!=), le (<=), gt (>), lt (<), or ge (>=).

ENDIANNESS is in be (big endian), le (little endian), or cpu (natural CPU endianness).

This waits until *addr COMP val is true, fetching addr with the given endianness.

Parameters:

• addr – An address to fetch data from
• val – Value to compare to

Example: srl_sched_wait_lt_be(addr, val) waits unitl the big-endian value pointed by addr is less than the constant passed in val.

srl_callback_t

int8_t srl_callback_t(uint32_t val)

Parameters:

• val – a passed value

Returns:

a boolean (0 is false)

void srl_sched_wait_priv(srl_callback_t *cb, uint32_t val)

This waits until callback returns true.

Parameters:

• cb – A callback function
• val – A value to pass to the callback function

Cache flush API

When dealing with SoC memory system, which is sometimes non-coherent, a cache control API may be useful. Here are the calls:

void srl_dcache_flush_addr(void *addr)

Removes the pointed data from the processor’s cache, if present.

Parameters:

• addr – An address.

void srl_dcache_flush_zone(void *addr, size_t size)

Removes all the lines matching the memory zone from processor’s cache.

Parameters:

• addr – An address.
• size – A size (in bytes)

Simulation control

void srl_abort()

Stops the execution as soon as possible. This is not guaranteed to succeed, as it sometimes makes no sense.

On simulated platforms, this may exit the simulator.