chris@umcp-cs.UUCP (Chris Torek) (04/27/85)
> What is the difference between "splnet" and "splimp"? splimp is about halfway between spl5 and spl6, and blocks IMP interrupts (and thus redirects et al., which is why you find it in routing code). splnet is between spl1 and spl4 (there is no spl2 or spl3) and blocks only software interrupts (net input is generally queued first, then processed via software interrupts). > I had a look at machine instructions of them in /sys/machine/asm.sed, > but I could not understand their roles completely becuase there is no > description for register 0x16 in /sys/machine/mtpr.h. There isn't any reference to register 0x16; both splimp and splnet read register 18 (IPL, the current interrupt priority level) and then stick a new value in it. "mtpr $0x16,$18" means put 16 in IPL, not put 18 in register 0x16.... -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 4251) UUCP: {seismo,allegra,brl-bmd}!umcp-cs!chris CSNet: chris@umcp-cs ARPA: chris@maryland
dmlee@cheviot.UUCP (Dongman Lee) (04/30/85)
What is the difference between "splnet" and "splimp"? I had a look at machine instructions of them in /sys/machine/asm.sed, but I could not understand their roles completely becuase there is no description for register 0x16 in /sys/machine/mtpr.h. What is the function of Reg.0x16? For the record, I am using VAX750/4.2BSD. Please mail me. Thanx in advance. T. A. D. Lee Arpa: dmlee%cheviot%newcastle.mailnet@mit-multics.arpa Uucp: UK!ukc!cheviot!dmlee
terryl@tekcrl.UUCP () (04/30/85)
>What is the difference between "splnet" and "splimp"? >I had a look at machine instructions of them in /sys/machine/asm.sed, but >I could not understand their roles completely becuase there is no description >for register 0x16 in /sys/machine/mtpr.h. >What is the function of Reg.0x16? >For the record, I am using VAX750/4.2BSD. splnet() and splimp() set the processor priority to different values, and looking at the asm.sed, it looks like splnet() is between a spl1() and spl4(), and splimp is between a spl5 and a spl6(), approx. Note I say approx. `cause the VAX has 32(or is it 16?My reference books are all at work...) different processor priority levels, and I'm trying to relate them to the 8 levels on a PDP.