freebsd-dev/sys/amd64/isa/vector.S
2003-05-03 00:21:43 +00:00

77 lines
2.7 KiB
ArmAsm

/*
* from: vector.s, 386BSD 0.1 unknown origin
* $FreeBSD$
*/
#include <amd64/isa/icu.h>
#include <amd64/isa/isa.h>
#include <amd64/isa/intr_machdep.h>
.data
ALIGN_DATA
/*
* Interrupt counters and names for export to vmstat(8) and friends.
*
* XXX this doesn't really belong here; everything except the labels
* for the endpointers is almost machine-independent.
*/
.globl intrcnt, eintrcnt
intrcnt:
.space INTRCNT_COUNT * 8
eintrcnt:
.globl intrnames, eintrnames
intrnames:
.space INTRCNT_COUNT * 32
eintrnames:
.text
/*
* Macros for interrupt interrupt entry, call to handler, and exit.
*
* XXX - the interrupt frame is set up to look like a trap frame. This is
* usually a waste of time. The only interrupt handlers that want a frame
* are the clock handler (it wants a clock frame), the npx handler (it's
* easier to do right all in assembler). The interrupt return routine
* needs a trap frame for rare AST's (it could easily convert the frame).
* The direct costs of setting up a trap frame are two pushl's (error
* code and trap number), an addl to get rid of these, and pushing and
* popping the call-saved regs %esi, %edi and %ebp twice, The indirect
* costs are making the driver interface nonuniform so unpending of
* interrupts is more complicated and slower (call_driver(unit) would
* be easier than ensuring an interrupt frame for all handlers. Finally,
* there are some struct copies in the npx handler and maybe in the clock
* handler that could be avoided by working more with pointers to frames
* instead of frames.
*
* XXX - should we do a cld on every system entry to avoid the requirement
* for scattered cld's?
*
* Coding notes for *.s:
*
* If possible, avoid operations that involve an operand size override.
* Word-sized operations might be smaller, but the operand size override
* makes them slower on on 486's and no faster on 386's unless perhaps
* the instruction pipeline is depleted. E.g.,
*
* Use movl to seg regs instead of the equivalent but more descriptive
* movw - gas generates an irelevant (slower) operand size override.
*
* Use movl to ordinary regs in preference to movw and especially
* in preference to movz[bw]l. Use unsigned (long) variables with the
* top bits clear instead of unsigned short variables to provide more
* opportunities for movl.
*
* If possible, use byte-sized operations. They are smaller and no slower.
*
* Use (%reg) instead of 0(%reg) - gas generates larger code for the latter.
*
* If the interrupt frame is made more flexible, INTR can push %eax first
* and decide the ipending case with less overhead, e.g., by avoiding
* loading segregs.
*/
#include "amd64/isa/icu_vector.S"