diff options
| author | Astrid Smith | 2011-10-20 22:30:09 -0700 |
|---|---|---|
| committer | Astrid Smith | 2011-10-20 22:30:09 -0700 |
| commit | f7e1599919eeabb8abf6f3402a0626300df5d4e7 (patch) | |
| tree | 678c89c4d4834faae3bece15653509bfbeb7f493 /interrupts.asm.m4 | |
| parent | 7540086d5b75a52d8af9dfa697b45160c010d023 (diff) | |
Interrupts and documentation changes
Diffstat (limited to 'interrupts.asm.m4')
| -rw-r--r-- | interrupts.asm.m4 | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/interrupts.asm.m4 b/interrupts.asm.m4 index 404f02f..7b4e522 100644 --- a/interrupts.asm.m4 +++ b/interrupts.asm.m4 @@ -1,7 +1,7 @@ -;;; interrupt handling code +;;; interrupt handling code, in -*- asm -*- ;; Current interrupt mode. IM 1 and friends will modify - ;; this, it can be any of 0, 1, 2. + ;; this. It can be any of 0, 1, 2. int_mode: dc.b 0 ;; 0 if the emulated device doesn't want interrupts. @@ -24,18 +24,20 @@ int_enabled: dc.b 1 ;; This emulator, on the other hand, will fetch the immediate ;; argument from the JP instruction in the shim, and then ;; dance off into la-la land. -int_opcode: dc.b 0 +int0_opcode: dc.b 0 dc.b $c3 ; JP immed.w -int_return: dc.w 0 ; the destination address +int0_return: dc.w 0 ; the destination address ;; This is the interrupt routine. It can come at any point ;; during an instruction, though routines that use a5 (e.g. by - ;; calling C subroutines) will have to turn off interrupts. + ;; calling C subroutines) will have to turn off or hold + ;; interrupts. + ;; ;; Routines that call into TIOS will have to remove this ;; interrupt handler. int_handler: - sub.l #4,a5 + sub.l #INT_OFFSET,a5 rte @@ -67,9 +69,10 @@ do_interrupt: ;; IM 0: A byte is placed on the bus and executed as if it ;; were inline in the program. This emulator will put that - ;; byte into int_opcode and set epc (or int_jump) to point + ;; byte into int0_opcode and set epc (or int_jump) to point ;; there. int_do_mode0: + move epc,int0_opcode rts ;; This routine emulates a mode 1 interrupt. |