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; Copyright 1996 Acorn Computers Ltd
;
; Licensed under the Apache License, Version 2.0 (the "License");
; you may not use this file except in compliance with the License.
; You may obtain a copy of the License at
;
; http://www.apache.org/licenses/LICENSE-2.0
;
; Unless required by applicable law or agreed to in writing, software
; distributed under the License is distributed on an "AS IS" BASIS,
; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
; See the License for the specific language governing permissions and
; limitations under the License.
;
; > ExtraSWIs
[ ProcessorVectors
;----------------------------------------------------------------------------------------
; ClaimProcVecSWI
;
; In: r0 = vector and flags
; bit meaning
; 0-7 vector number
; 0 = 'Branch through 0' vector
; 1 = Undefined instruction
; 2 = SWI
; 3 = Prefetch abort
; 4 = Data abort
; 5 = Address exception (only on ARM 2 & 3)
; 6 = IRQ
; 7+ = reserved for future use
; 8 0 = release
; 1 = claim
; 9-31 reserved (set to 0)
; r1 = replacement value
; r2 = value which should currently be on vector (only needed for release)
;
; Out: r1 = value which has been replaced (only returned on claim)
;
; Allows a module to attach itself to one of the processor vectors.
;
ClaimProcVecSWI ROUT
Entry "r3-r5"
AND r3, r0, #&FF ; Get vector number.
CMP r3, #(ProcVec_End-ProcVec_Start):SHR:2
ADRCSL r0, ErrorBlock_BadClaimNum
BCS %FT30
MOV r4, r1 ; r4 = replacement value
LDR r5, =ZeroPage+ProcVec_Start
PHPSEI ; Disable IRQs while we mess around with vectors.
TST r0, #1:SHL:8
LDRNE r1, [r5, r3, LSL #2]! ; If claiming then return current value (r5->vector to replace).
BNE %FT10
LDR r3, [r5, r3, LSL #2]! ; Releasing so get current value (r5->vector to replace).
TEQ r2, r3 ; Make sure it's what the caller thinks it is.
ADRNEL r0, ErrorBlock_NaffRelease
BNE %FT20
10
STR r4, [r5] ; Store replacement value.
PLP ; Restore IRQs.
PullEnv
ExitSWIHandler
20
PLP ; Restore IRQs and return error.
30
[ International
BL TranslateError
]
PullEnv
B SLVK_SetV
]
END