; 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.
;
TTL => NewIRQs
; *****************************************************************************
;
; Main IRQ routine:
; Push workregs,lr
; IRQsema -> TOS
; stack -> IRQsema
; call IRQ1V
; IRQs off
; TOS ->IRQsema
; process callback, pulling workregs,pc at some point
;
; *****************************************************************************
ALIGN 32
Initial_IRQ_Code ROUT
SUB lr, lr, #4
Push "r0, lr"
MRS lr, SPSR
Push "r1-r3, r11, r12, lr"
; ** For Pete's sake remember to change the heap manager if you change the above
; ** register list!!!!!!! And the [sp_irq, #4*5] below
LDR r12, =ZeroPage
LDR r0, [r12, #IRQsema]
Push r0
STR sp_irq, [r12, #IRQsema]
MOV lr, pc
LDR pc, [r12, #IRQ1V]
; IRQ1V called with r0-r3,r11,r12 trashable. r12=0
; Stu has a theory that 1N cycle can be saved by the default IRQ1V pointing
; at a location containing a branch to our code; we then do something like
; LDR R0, [R12, #IRQ1V]
; CMP R0, #OurIRQ1V
; BNE somebodysonIRQ1V
; .... fall into default IRQ1V code
Push "r10"
MOV r10, #UnthreadV
BL CallVector
Pull "r10"
LDR r11, =ZeroPage
Pull r0
STR r0, [r11, #IRQsema]
LDRB r11, [r11, #CallBack_Flag]
TEQ r11, #0
BNE %FT10
05
MyCLREX r0, r1
Pull "r1-r3, r11, r12, lr"
MSR SPSR_cxsf, lr
Pull "r0, pc",, ^
10
TST r11, #CBack_Postpone
LDREQ lr, [sp_irq, #4*5] ; get SPSR off stack
TSTEQ lr, #I32_bit :OR: &0F ; check we came from USR26 or USR32 mode, with IRQs enabled
BNE %BT05
; Do a CallBack: asked for, not postponed, and we're returning into USR26/32 mode.
ASSERT IRQ32_mode :AND: SVC32_mode = IRQ32_mode ; so the following dodgy ops work
Pull "r1-r3, r11, r12"
MRS r0, CPSR
ORR r0, r0, #SVC32_mode
MSR CPSR_c, r0
Push "r10-r12" ; push r10-r12 onto the SVC stack
BIC r0, r0, #IRQ32_mode :EOR: SVC32_mode
MSR CPSR_c, r0
Pull "r10-r12" ; SPSR, R0, LR really
ORR r0, r0, #SVC32_mode
MSR CPSR_c, r0
Push r12 ; Save the return address
MOV r14, r10 ; SPSR into R14
MOV r0, r11 ; restore original R0
LDR r10, =ZeroPage
LDRB r11, [r10, #CallBack_Flag]
B Do_CallBack_postpone_already_clear
LTORG
; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
; Default IRQ1V: despatch on interrupting device
; Now copied to RAM, together with vector entries and device tables
^ 0
IRQDesp_Link # 4
IRQDesp_R12Val # 4
IRQDesp_CallAddr # 4
IRQDesp_Link_Unshared * 1 ; flag in Link (for _this_ node)
ASSERT IRQDesp_CallAddr = IRQDesp_R12Val + 4
DefaultIRQ1Vcode ROUT
Push "r9,lr"
[ ZeroPage = 0
MOV r9, #0
|
LDR r9, %FT02
]
AddressHAL r9 ; modifies r9
CallHAL HAL_IRQSource
Pull "r9"
ADR r2, Devices
ADD r1, r0, r0, LSL #1 ; multiply by 3
ADD r11, r2, r1, LSL #2 ; so table contains DevNo * 3
01 MOV lr, pc
LDMIA r11, {r11, r12, pc}
TST r11, #IRQDesp_Link_Unshared
BEQ %BT01
Pull pc
[ ZeroPage <> 0
02
DCD ZeroPage
]
; ******* IRQ device handlers entered with r0-r3,r11,r12,r14 trashable *******
; r0 = device number (if HAL)
; r3 -> IOC (not in HAL world, unless IOMD HAL is helpful)
; r12 = what they asked for
; r14 = return address to MOS IRQ exit sequence
DefaultIRQ1Vcode_end
Devices * DefaultIRQ1Vcode_end + 12
NoInterrupt * -1
DevicesEnd * Devices + MaxInterrupts * 12
ASSERT DevicesEnd - DefaultIRQ1Vcode <= DefIRQ1Vspace
; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
InitialiseIRQ1Vtable
Push "v1-v3,sb,lr"
; copy IRQ handler: not done with rest of copying
; because soft break needs the info to free any claimed blocks.
LDR a1, =DefaultIRQ1V
ADRL a2, DefaultIRQ1Vcode
ADRL a3, DefaultIRQ1Vcode_end
CopyDefaultIRQ1V
LDR a4, [a2], #4
STR a4, [a1], #4
CMP a2, a3
BNE CopyDefaultIRQ1V
AddressHAL
ADD v1, a1, #12
ADD a3, v1, #MaxInterrupts*12
MOV a2, #0
MOV a4, #-1
LDR ip, =IRQ
FillInDefaultIRQ1VDevices
STMIA a1!, {a2, a4, ip}
ADD a4, a4, #1
CMP a1, a3
BNE FillInDefaultIRQ1VDevices
; Now fill in our basic device handlers. First the timer.
MOV a1, #0
CallHAL HAL_TimerDevice
LDR a2, =ZeroPage+OsbyteVars
LDR a3, =TickOne
ADD a1, a1, a1, LSL #1
ADD a1, v1, a1, LSL #2
STMIB a1, {a2, a3}
1
[ NumberOfPodules > 0
; Now Podule bits
MOV a1, #IRQDesp_Link_Unshared
LDR a2, =ZeroPage+PFIQasIRQ_Chain - (PodDesp_Link-PodDesp_R12Val)
ADR a3, PFIQasIRQ_Despatch
ADD lr, v1, #PFIQasIRQ_DevNo*12
STMIA lr, {a1, a2, a3}
LDR a2, =ZeroPage+PIRQ_Chain - (PodDesp_Link-PodDesp_R12Val)
ADR a3, PIRQ_Despatch
ADD lr, v1, #Podule_DevNo*12
STMIA lr, {a1, a2, a3}
]
; Now IIC - if any
LDR v2, =ZeroPage+IICBus_Base
MOV v3, #0
80
LDR a1, [v2, #IICBus_Type]
TST a1, #IICFlag_HighLevel
TSTNE a1, #IICFlag_Background
BEQ %FT90
MOV a1, v3
CallHAL HAL_IICDevice
; I think it's safe to call A SWI here...
LDR r1, =IICIRQ
MOV r2, v3
SWI XOS_ClaimDeviceVector
90
ADD v2, v2, #IICBus_Size
ADD v3, v3, #1
CMP v3, #IICBus_Count
BNE %BT80
Pull "v1-v3,sb,pc"
; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
; Specialist despatchers for podules
^ 0
PodDesp_Address # 4 ; address of IRQ status byte
PodDesp_Mask # 4 ; for use on above
PodDesp_R12Val # 4
PodDesp_CallAddr # 4 ; address to call if (?Address EOR (Mask>>8)) AND Mask <> 0
PodDesp_Link # 4 ; next node
PodDesp_NodeSize # 0
; In r12 = PFIQasIRQ_Chain - (PodDesp_Link-PodDesp_R12Val)
; or PIRQ_Chain - (PodDesp_Link-PodDesp_R12Val) from despatcher
PFIQasIRQ_Despatch ROUT
PIRQ_Despatch ; All the same thing now
01 LDR r12, [r12, #PodDesp_Link-PodDesp_R12Val]
LDMIA r12!, {r1, r2} ; address and mask
; TMD 09-Jun-89: Don't corrupt r0 - it's needed by the default IRQ2 routine
LDRB r1, [r1]
EOR r1, r1, r2, LSR #8
ANDS r1, r1, r2
BEQ %BT01
LDMIA r12, {r12, pc}
Default_PIRQHandler_Node
Default_PFIQasIRQHandler_Node
& .+4 ; address we know has non-zero value!
& -1 ; mask
& 0 ; handler r12
& IRQ ; handler code
& 0 ; null link for naff release checking
; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
; Claim of device vectors
; r0 = Device number
; r1 = call address
; r2 = r12 value
; r3 = interrupt location } when podules are
; r4 = interrupt mask/polarity } supported and r0 = podule device number
CDV_Flags * &FF000000
CDV_Shared * 1:SHL:31
DeviceVector_Claim ROUT
Push "r0-r3, lr"
01 SWI XOS_ReleaseDeviceVector ; Release until bored
BVC %BT01
LDR r0, [sp]
BIC r0, r0, #CDV_Flags
LDR lr, =ZeroPage
LDR lr, [lr, #IRQMax]
CMP r0, lr
BHS DV_Fail_NaffDevNo
[ NumberOfPodules > 0
! 0, "ClaimDeviceVector has podule IRQ/FIQs assembled in"
CMP r0, #Podule_DevNo
CMPNE r0, #PFIQasIRQ_DevNo
BEQ PoduleChainClaim
]
MOV r3, #12
BL ClaimSysHeapNode
BVS DV_Exit
LDR r11, [sp]
BIC r0, r11, #CDV_Flags
ADD r0, r0, r0, LSL #1 ; *3
LDR r1, =DefaultIRQ1V-DefaultIRQ1Vcode+Devices
ADD r1, r1, r0, LSL #2
WritePSRc SVC_mode+I_bit, r10 ; IRQs off for update (on again on SWI exit)
LDMIA r1, {r0, r3, r10}
STMIA r2, {r0, r3, r10} ; copy current head into node
MOV r10, r2
TST r11, #CDV_Shared
ORREQ r10, r10, #IRQDesp_Link_Unshared
LDR r11, [sp, #4*2] ; r12 value
LDR r12, [sp, #4*1] ; call address
STMIA r1, {r10-r12} ; copy given info into head
DV_Exit STRVS r0, [sp] ; Common exit for both claim + release
Pull "r0-r3, lr"
B SLVK_TestV
DV_Fail_NaffDevNo
ADR r0, ErrorBlock_NaffDevNo
[ International
BL TranslateError
|
SETV
]
B DV_Exit
MakeErrorBlock NaffDevNo
[ NumberOfPodules > 0
PoduleChainClaim
MOV r3, #PodDesp_NodeSize
BL ClaimSysHeapNode
BVS DV_Exit
MOV r10, r2
LDMFD sp, {r0-r3}
STR r1, [r10, #PodDesp_CallAddr]
STR r2, [r10, #PodDesp_R12Val]
STR r3, [r10, #PodDesp_Address]
STR r4, [r10, #PodDesp_Mask]
CMP r0, #Podule_DevNo
LDREQ r0, =ZeroPage+PIRQ_Chain
LDRNE r0, =ZeroPage+PFIQasIRQ_Chain
WritePSRc SVC_mode+I_bit, r1 ; IRQs off for update
LDR r1, [r0]
STR r1, [r10, #PodDesp_Link]
STR r10, [r0]
B DV_Exit
]
; .............................................................................
; Release of device vectors
; r0 = Device number
; r1 = call address
; r2 = r12 value
; r0 = PFIQ|PIRQ devno -> r3 = interrupt location (LDRB always used)
; r4 = interrupt mask
DeviceVector_Release ROUT
Push "r0-r3, lr" ; Ensure same regset as above
BIC r0, r0, #CDV_Flags
LDR lr, =ZeroPage
LDR lr, [lr, #IRQMax]
CMP r0, lr
BHS DV_Fail_NaffDevNo
WritePSRc SVC_mode + I_bit, r12 ; IRQs off while holding context
[ NumberOfPodules > 0
! 0, "ReleaseDeviceVector has podule IRQ/FIQs assembled in"
CMP r0, #Podule_DevNo
CMPNE r0, #PFIQasIRQ_DevNo
BEQ PoduleChainRelease
]
ADD r0, r0, r0, LSL #1 ; *3
LDR r12, =DefaultIRQ1V-DefaultIRQ1Vcode+Devices
ADD r12, r12, r0, LSL #2 ; address of node
MOV r11, #-1 ; "fudge" predecessor node
01 LDMIB r12, {r3, r10}
CMP r3, r2
CMPEQ r10, r1
BEQ %FT02 ; found it
MOV r11, r12
LDR r12, [r12, #IRQDesp_Link]
BICS r12, r12, #IRQDesp_Link_Unshared
BNE %BT01
11 ADR r0, ErrorBlock_BadDevVecRel
[ International
BL TranslateError
|
SETV
]
B DV_Exit
MakeErrorBlock BadDevVecRel
02 CMP r11, #-1
BEQ %FT03
MOV r2, r12
LDR r12, [r2, #IRQDesp_Link]
LDR r14, [r11, #IRQDesp_Link] ; preserve r11's "unshared" flag
BIC r12, r12, #IRQDesp_Link_Unshared
AND r14, r14, #IRQDesp_Link_Unshared
ORR r12, r12, r14
STR r12, [r11, #IRQDesp_Link] ; node delinked
B %FT04
03 LDR r2, [r12, #IRQDesp_Link]; freeable = nextnode
BIC r2, r2, #IRQDesp_Link_Unshared
LDMIA r2, {r0, r1, r3} ; copy next node into head posn
STMIA r12, {r0, r1, r3}
04
BL FreeSysHeapNode ; free block
B DV_Exit
[ NumberOfPodules > 0
PoduleChainRelease
CMP r0, #Podule_DevNo
LDREQ r0, =ZeroPage+PIRQ_Chain-PodDesp_Link
LDRNE r0, =ZeroPage+PFIQasIRQ_Chain-PodDesp_Link
10 LDR r12, [r0, #PodDesp_Link]
CMP r12, #0
BEQ %BT11
LDR r11, [r12, #PodDesp_Address]
CMP r11, r3
LDREQ r11, [r12, #PodDesp_Mask]
CMPEQ r11, r4
LDREQ r11, [r12, #PodDesp_CallAddr]
CMPEQ r11, r1
LDREQ r11, [r12, #PodDesp_R12Val]
CMPEQ r11, r2
MOVNE r0, r12
BNE %BT10
LDR r11, [r12, #PodDesp_Link]
STR r11, [r0, #PodDesp_Link]
MOV r2, r12
B %BT04
]
; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
; Default device owner for IRQ not recognised by system: pass to IRQ2V
IRQ ROUT
Push "r10, lr"
MOV r10, #IrqV
BL CallVector
Pull "r10, lr"
Pull "pc" ; new-style CDV - pull return address
; *****************************************************************************
; Default IRQ2V:
; r0 must still have devno in it
; r12 is 0 (from vector)
; Clear mask, clear IRQ as appropriate/possible
NOIRQ ROUT
TEQ r0, #0
Pull pc, MI
MOV r11, r9
AddressHAL
CallHAL HAL_IRQDisable
MOV r9, r11
Pull pc ; claim vector
; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
; The following bits have been appropriated from source.pmf.oseven to make
; sure Tim's old code doesn't overwrite us when he gets back!
; SWI OS_GenerateEvent: call event vector if enabled
GenEvent ROUT
Push lr
WritePSRc SVC_mode+I_bit, lr ; Disable IRQs. MUST call these ones
BL OSEVEN ; in SVC mode as people expect it
Pull lr
B SLVK
; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
; Subroutine call version
; In r0 = event type
; r1,r2 parameters
; Out C=0 => event was enabled, or was >= 32 anyway
; C=1 => event was disabled, so vector not called
OSEVEN ROUT
Push lr
CMP r0, #31 ; Events >= 32 are ALWAYS raised. SKS
; flags are HI if so, ie. NE
[ ZeroPage = 0
LDRLSB r14, [r0, #OsbyteVars + :INDEX: EventSemaphores]
|
LDRLS r14, =ZeroPage+OsbyteVars+:INDEX:EventSemaphores
LDRLSB r14, [r0, r14]
]
; get semaphore for this event 0..31
CMPLS r14, #0 ; non-zero => enabled
Pull pc, EQ ; if disabled, exit with C=1
Push "r0-r3, r10-r12" ; r3 excessive ???
MOV r10, #EventV ; call event vector
BL CallVector
CLC ; indicate event enabled
Pull "r0-r3, r10-r12, pc"
; ...................... default owner of EventV ..............................
; Call Event handler
; In r12 = EvtHan_ws
DefEvent ROUT
MOV lr, pc ; link with all the bits
LDMIA r12, {r12, pc} ; call EventHandler, returns to ...
TEQ r12, #1
Pull pc,NE
[ ZeroPage = 0
LDRB r14, [r12, #CallBack_Flag-1] ; IRQs are still disabled
ORR r14, r14, #CBack_OldStyle
STRB r14, [r12, #CallBack_Flag-1]
|
LDR r12, =ZeroPage
LDRB r14, [r12, #CallBack_Flag] ; IRQs are still disabled
ORR r14, r14, #CBack_OldStyle
STRB r14, [r12, #CallBack_Flag]
]
Pull pc ; claim EventV
; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
; Process timer zero IRQ device (100Hz clock)
; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
ALIGN 32
TickOne ROUT
; Don't push r14 - we're using new interface, and claim the vector
Push "r0,r9,r12"
AddressHAL
; In some chips, Timer0 is latched in the timer block instead of,
; or as well as in the interrupt controller
MOV R0, #0 ; clear latch for Timer0
CallHAL HAL_TimerIRQClear
Pull "r0" ; get device number back
CallHAL HAL_IRQClear
Pull "r9,r12"
LDR R1, =ZeroPage
LDR R0, [R1, #MetroGnome]
ADD R0, R0, #1
STR R0, [R1, #MetroGnome]
LDRB R0, CentiCounter ; Counter for VDU CTRL timing
SUBS R0, R0, #1
STRCSB R0, CentiCounter ; decrement if not zero
LDR R0, IntervalTimer +0
ADDS R0, R0, #1 ; Increment the low 4 bytes
STR R0, IntervalTimer +0
LDREQB R0, IntervalTimer +4
ADDEQ R0, R0, #1 ; and carry into 5th byte if necessary
STREQB R0, IntervalTimer +4
Push "R4,R12" ; R0-R3 already pushed
TEQEQ R0, #&100 ; has interval timer crossed zero ?
MOVEQ R0, #Event_IntervalTimer ; Event ITCZ
BLEQ OSEVEN
BL CentiSecondTick ; Notify keyboard of a centisecond
Pull "R4,R12"
LDR R0, RealTime +0 ; Increment 5-byte real time
ADDS R0, R0, #1
STR R0, RealTime +0
LDRCSB R0, RealTime +4
ADDCS R0, R0, #1 ; Won't wrap until 2248 and then it
STRCSB R0, RealTime +4 ; all falls over anyway
LDRB R0, TimerState ; get switch state
TEQ R0, #5 ; toggles between 5 and 10
LDREQ R1, TimerAlpha +0 ; either load from one
LDREQB R2, TimerAlpha +4
LDRNE R1, TimerBeta +0 ; or the other
LDRNEB R2, TimerBeta +4
ADREQ R3, TimerBeta +0 ; and point to t'other
ADRNE R3, TimerAlpha +0
ADDS R1, R1, #1 ; increment
ADC R2, R2, #0 ; with carry
STR R1, [R3] ; and store back
STRB R2, [R3, #4]
EOR R0, R0, #&0F ; 5 <-> 10
STRB R0, TimerState
Push R10
MOV R10, #TickerV ; call 100Hz vector
BL CallVector ; IRQ's still disabled
BL ProcessTickEventChain ; Re-enables IRQs
Pull "R10,PC"
; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
; Process VSync IRQ device
; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
ALIGN 32
FalseVsyncIRQ ROUT
LDR R1, =ZeroPage
LDR R0, [R1, #MetroGnome]
TST R0, #1
MOVEQ pc, lr
Push "lr"
; Fall through...
VsyncIRQ_ExtEntry ROUT
LDRB R0, CFStime ; decrement 'CFS' timer !
SUB R0, R0, #1
STRB R0, CFStime
VDWS WsPtr ; Do our stuff before issuing VSYNC event
BL VsyncCall
BYTEWS WsPtr
MOV R0, #Event_VSync ; VSYNC event number
BL OSEVEN
LDRB R1, FlashCount
SUBS R1, R1, #1
Pull PC, CC ; was zero, so frozen
STRNEB R1, FlashCount ; else if now non-zero, store it back
Pull PC, NE ; not time to flash yet
LDRB R1, FlashState ; Get the state and
EORS R1, R1, #1 ; flip to the other one (setting flags)
STRB R1, FlashState
LDREQB R2, SpacPeriod ; get appropriate new period
LDRNEB R2, MarkPeriod
STRB R2, FlashCount ; and put into counter
VDWS WsPtr
Push R4
BEQ dothesecondflash
dothefirstflash
BL DoFirstFlash
Pull "R4, PC"
dothesecondflash
BL DoSecondFlash
Pull "R4, PC"
; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
END