Compaq 21264 Hardware Reference Manual page 321

If "CBOX_ERR[C_ADDR]" has not changed when the CRD_HANDLER is re-
entered, or "CBOX_ERR[C_STAT] == 0x0", all cache locations should be evicted to
avoid the live lock described above.
; Sample code for evicting cache.
; This method loads a 64K block, then exits the CRD_HANDLER
; to check if the sberr has been evicted. If not it loads the next 64K block.
; In the sample code below,
; sx is a shadow register
; ldi is a macro that loads a 64-bit constant into the specified register
full_scrub:
hw_ldq/p
ldi
ldi
ldi
ldi
addq
ble
bis
hw_stq/p
subq
mb
.align 4, NOP_OPCODE
blbc
br
.align 4, NOP_OPCODE
next_reread:
; ******** four cache blocks
; Evict dcache by prefetching to all dcache indexes.
; use 'hw_ldl r31 xxxx' Normal Prefetch
; Do not use 'hw_ldq/p r31 xxx' Prefetch,
; Evict Next because this will always access the same set in dcache.
hw_ldl/p
hw_ldl/p
hw_ldl/p
hw_ldl/p
hw_ldl/p
hw_ldl/p
hw_ldl/p
hw_ldl/p
subq
subq
ble
br
bsr
Alpha 21264/EV67 Hardware Reference Manual
Restriction 47: Cache Eviction for Single-Bit Cache Errors
s5, 104(r31)
s1, ^x200
s2, ^x1C0
s3, ^x10000
s4, ^x2000000
s3,s5,s5
s5, s4, <.+4>
r31, r31, s5
s5, 104(r31)
s5, s2, s5
r31, <.+4>
r31, <.-4>
r31,^x1C0(s5)
r31,^x180(s5)
r31,^x140(s5)
r31,^x100(s5)
r31,^xC0(s5)
r31,^x80(s5)
r31,^x40(s5)
r31,^x00(s5)
s5, s1, s5
s3, s1, s3
s3, <.+4>
r31, next_reread
s7, sys__cbox
; Loop dec value
; Start offset
; Block size (64K -> size of dcache)
; 2X bcache size
; Skip next instruction if ADDR
; .le. 2X bcache
; Set ADDR = 0x0
; Store ADDR for next pass thru
; Make sure no speculative loads
; happen in the CRD handler
; |
; |
; V
; Make sure no speculative loads
; happen in the CRD handler
; Re-read the bad block QW #0
; Re-read the bad block QW #0
; Re-read the bad block QW #0
; Re-read the bad block QW #0
; Re-read the bad block QW #0
; Re-read the bad block QW #0
; Re-read the bad block QW #0
; Re-read the bad block QW #0
; Decrement addr
; Decrement counter
; Read and clean cbox error ipr
PALcode Restrictions and Guidelines
D–23