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NMIExceptionHandler: Don't save callee-saved registers, fix stack alignment

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NMI routine sdk_wDev_ProcessFiq seems to be written in C, meets ABI
calling conventions for callee-saved registers. Not sure why SDK
handlers saved them.

NMI handler now also meets the ABI requirement that stack is 16 byte
aligned (doesn't seem strictly necessary, but can't hurt.)
This commit is contained in:
Angus Gratton 2015-09-29 14:51:24 +10:00
parent 4448380c5e
commit 697d5b72bc
1 changed files with 33 additions and 39 deletions
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72
core/exception_vectors.S
View file

@ -25,10 +25,12 @@
.section .bss
.balign 16
NMIHandlerStack: # stack space for NMI handler
.skip 4*0x100
.NMIHandlerStackTop:
.balign 16
LoadStoreErrorHandlerStack:
.word 0 # a0
.word 0 # (unused)
@ -374,60 +376,52 @@ NMIExceptionHandler:
.type NMIExceptionHandler, @function
wsr sp, excsave3 # excsave3 holds user stack
movi sp, .NMIHandlerStackTop - 0x54
movi sp, .NMIHandlerStackTop - 0x40
s32i a0, sp, 0x00
s32i a2, sp, 0x08
s32i a3, sp, 0x0c
s32i a4, sp, 0x10
s32i a5, sp, 0x14
s32i a6, sp, 0x18
s32i a7, sp, 0x1c
s32i a8, sp, 0x20
s32i a9, sp, 0x24
s32i a10, sp, 0x28
s32i a11, sp, 0x2c
s32i a12, sp, 0x30
s32i a13, sp, 0x34
s32i a14, sp, 0x38
s32i a15, sp, 0x3c
s32i a2, sp, 0x04
s32i a3, sp, 0x08
s32i a4, sp, 0x0c
s32i a5, sp, 0x10
s32i a6, sp, 0x14
s32i a7, sp, 0x18
s32i a8, sp, 0x1c
s32i a9, sp, 0x20
s32i a10, sp, 0x24
s32i a11, sp, 0x28
rsr a0, epc1
s32i a0, sp, 0x40
s32i a0, sp, 0x2c
rsr a0, exccause
s32i a0, sp, 0x44
s32i a0, sp, 0x30
rsr a0, excsave1
s32i a0, sp, 0x48
s32i a0, sp, 0x34
rsr a0, excvaddr
s32i a0, sp, 0x4c
s32i a0, sp, 0x38
rsr a0, sar
s32i a0, sp, 0x50
s32i a0, sp, 0x3c
movi a0, 0x23 # Override PS for NMI handler
wsr a0, ps
rsync
call0 sdk_wDev_ProcessFiq
l32i a0, sp, 0x50
l32i a0, sp, 0x3c
wsr a0, sar
l32i a0, sp, 0x4c
l32i a0, sp, 0x38
wsr a0, excvaddr
l32i a0, sp, 0x48
l32i a0, sp, 0x34
wsr a0, excsave1
l32i a0, sp, 0x44
l32i a0, sp, 0x30
wsr a0, exccause
l32i a0, sp, 0x40
l32i a0, sp, 0x2c
wsr a0, epc1
l32i a15, sp, 0x3c
l32i a14, sp, 0x38
l32i a13, sp, 0x34
l32i a12, sp, 0x30
l32i a11, sp, 0x2c
l32i a10, sp, 0x28
l32i a9, sp, 0x24
l32i a8, sp, 0x20
l32i a7, sp, 0x1c
l32i a6, sp, 0x18
l32i a5, sp, 0x14
l32i a4, sp, 0x10
l32i a3, sp, 0x0c
l32i a11, sp, 0x28
l32i a10, sp, 0x24
l32i a9, sp, 0x20
l32i a8, sp, 0x1c
l32i a7, sp, 0x18
l32i a6, sp, 0x14
l32i a5, sp, 0x10
l32i a4, sp, 0x0c
l32i a3, sp, 0x08
movi a0, 0x33 # Reset PS
wsr a0, ps
rsync
@ -438,7 +432,7 @@ NMIExceptionHandler:
movi a0, 0x3ff00000
movi a2, 0x1
s32i a2, a0, 0
l32i a2, sp, 0x08
l32i a2, sp, 0x04
l32i a0, sp, 0x00
movi a1, 0x0
xsr a1, excsave3 # Load stack back from excsave3, clear excsave3