how are arguments of sbi function passed to SEE?

[agrobman]

Sorry, maybe I missed something, but how do the sbi functions pass their parameters to SEE.

the a7 is used to pass EID a6 is used to pass FID,

what register is used to pass stime_value in sbi_set_timer function, for ex? Are these a0,a1 ... as ABI mandate?

[repnop]

Since no one has answered you yet, its spelled out in this section of the specification:

This binary encoding matches the RISC-V Linux syscall ABI, which itself is based on the calling convention defined in the RISC-V ELF psABI.

Now if we look at the calling convention specification:

Name	ABI Mnemonic	Meaning	Preserved across calls?
x0	zero	Zero	-- (Immutable)
x1	ra	Return address	No
x2	sp	Stack pointer	Yes
x3	gp	Global pointer	-- (Unallocatable)
x4	tp	Thread pointer	-- (Unallocatable)
x5 - x7	t0 - t2	Temporary registers	No
x8 - x9	s0 - s1	Callee-saved registers	Yes
x10 - x17	a0 - a7	Argument registers	No
x18 - x27	s2 - s11	Callee-saved registers	Yes
x28 - x31	t3 - t6	Temporary registers	No

So arguments are passed to the SBI implementation in order of a0 to a5, with a6 and a7 being overridden by this specification to specifically be the FID and EID, respectively, for calls.

[agrobman]

thanks for clarification..