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removed inlining in wait.c, added (simple) map-based MMU handling

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Markus Fröschle
2014-01-18 14:03:25 +00:00
parent 6d0643b885
commit a612252d9a
6 changed files with 220 additions and 134 deletions
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26
BaS_gcc/sys/exceptions.S
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@@ -387,50 +387,30 @@ reset_vector:
// Triggered when code tries to access a memory area that is not known to the MMU yet.
// This is either a "classic" bus error or the MMU hit a "legal" page not yet mapped.
//
// CAVEAT: if this happens due to the supervisor stack crossing a page boundary, we
// cannot use the supervisor stack in here. Therefore we first switch to a safe stack
// (RAMBAR0, the processor internal SRAM)
access_exception:
// save current SSP
move.l sp,__SUP_SP // defined in linker script: top of SRAM0
lea __SUP_SP - 4,sp // now we can savely use this as stack
// save gcc scratch registers, others will be handled by called function
lea -4*4(sp),sp
movem.l d0-d1/a0-a1,(sp)
move.l __SUP_SP,a0 // original stack pointer
lea 4*4(sp),a0 // original stack pointer
move.l (a0),-(sp) // format status word
move.l 4(a0),-(sp) // program counter at access error
jsr _access_exception // note the undescore
jsr _access_exception // note the underscore
lea 2*4(sp),sp // adjust stack
tst.l d0 // handled?
beq bus_error // no
movem.l (sp),d0-d1/a0-a1 // restore scratch registers
lea 4*4(sp),sp
// revert stack trickery
move.l __SUP_SP,sp
beq bus_error // no
rte
bus_error:
movem.l (sp),d0-d1/a0-a1 // restore scratch registers
lea 4*4(sp),sp
// revert stack trickery
move.l __SUP_SP,sp // restore original stack
bra std_exc_vec
zero_divide: