/*
* This file contains the basic algorithms for all assembly code used
* in an specific CPU port of RTEMS. These algorithms must be implemented
* in assembly language
*
* History:
* Baseline: no_cpu
* 1996: Ported to MIPS64ORION by Craig Lebakken <craigl@transition.com>
* COPYRIGHT (c) 1996 by Transition Networks Inc.
* To anyone who acknowledges that the modifications to this file to
* port it to the MIPS64ORION are provided "AS IS" without any
* express or implied warranty:
* permission to use, copy, modify, and distribute this file
* for any purpose is hereby granted without fee, provided that
* the above copyright notice and this notice appears in all
* copies, and that the name of Transition Networks not be used in
* advertising or publicity pertaining to distribution of the
* software without specific, written prior permission. Transition
* Networks makes no representations about the suitability
* of this software for any purpose.
* 2000: Reworked by Alan Cudmore <alanc@linuxstart.com> to become
* the more general MIPS port. Joel Sherrill <joel@OARcorp.com>
* continued this rework, rewriting as much as possible in
* C and testing on the TX39.
*
* COPYRIGHT (c) 1989-2000.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* $Id$
*/
#include <asm.h>
#include "iregdef.h"
#include "idtcpu.h"
#define EXCP_STACK_SIZE (NREGS*R_SZ)
#define ISR_VEC_SIZE 4
#if 1 /* 32 bit unsigned32 types */
#define sint sw
#define lint lw
#define stackadd addiu
#define intadd addu
#define SZ_INT 4
#define SZ_INT_POW2 2
#else /* 64 bit unsigned32 types */
#define sint dw
#define lint dw
#define stackadd daddiu
#define intadd daddu
#define SZ_INT 8
#define SZ_INT_POW2 3
#endif
#ifdef __GNUC__
#define EXTERN(x,size) .extern x,size
#else
#define EXTERN(x,size)
#endif
/* NOTE: these constants must match the Context_Control structure in cpu.h */
#define S0_OFFSET 0
#define S1_OFFSET 1
#define S2_OFFSET 2
#define S3_OFFSET 3
#define S4_OFFSET 4
#define S5_OFFSET 5
#define S6_OFFSET 6
#define S7_OFFSET 7
#define SP_OFFSET 8
#define FP_OFFSET 9
#define RA_OFFSET 10
#define C0_SR_OFFSET 11
#define C0_EPC_OFFSET 12
/* NOTE: these constants must match the Context_Control_fp structure in cpu.h */
#define FP0_OFFSET 0
#define FP1_OFFSET 1
#define FP2_OFFSET 2
#define FP3_OFFSET 3
#define FP4_OFFSET 4
#define FP5_OFFSET 5
#define FP6_OFFSET 6
#define FP7_OFFSET 7
#define FP8_OFFSET 8
#define FP9_OFFSET 9
#define FP10_OFFSET 10
#define FP11_OFFSET 11
#define FP12_OFFSET 12
#define FP13_OFFSET 13
#define FP14_OFFSET 14
#define FP15_OFFSET 15
#define FP16_OFFSET 16
#define FP17_OFFSET 17
#define FP18_OFFSET 18
#define FP19_OFFSET 19
#define FP20_OFFSET 20
#define FP21_OFFSET 21
#define FP22_OFFSET 22
#define FP23_OFFSET 23
#define FP24_OFFSET 24
#define FP25_OFFSET 25
#define FP26_OFFSET 26
#define FP27_OFFSET 27
#define FP28_OFFSET 28
#define FP29_OFFSET 29
#define FP30_OFFSET 30
#define FP31_OFFSET 31
/*PAGE
*
* _CPU_ISR_Get_level
*
* unsigned32 _CPU_ISR_Get_level( void )
*
* This routine returns the current interrupt level.
*/
#if __mips == 3
/* return the current exception level for the 4650 */
FRAME(_CPU_ISR_Get_level,sp,0,ra)
mfc0 v0,C0_SR
nop
andi v0,SR_EXL
srl v0,1
j ra
ENDFRAME(_CPU_ISR_Get_level)
FRAME(_CPU_ISR_Set_level,sp,0,ra)
nop
mfc0 v0,C0_SR
nop
andi v0,SR_EXL
beqz v0,_CPU_ISR_Set_1 /* normalize v0 */
nop
li v0,1
_CPU_ISR_Set_1:
beq v0,a0,_CPU_ISR_Set_exit /* if (current_level != new_level ) */
nop
bnez a0,_CPU_ISR_Set_2
nop
nop
mfc0 t0, C0_SR
nop
li t1,~SR_EXL
and t0,t1
nop
mtc0 t0,C0_SR /* disable exception level */
nop
j ra
nop
_CPU_ISR_Set_2:
nop
mfc0 t0,C0_SR
nop
li t1,~SR_IE
and t0,t1
nop
mtc0 t0,C0_SR /* first disable ie bit (recommended) */
nop
ori t0, SR_EXL|SR_IE /* enable exception level */
nop
mtc0 t0,C0_SR
nop
_CPU_ISR_Set_exit:
j ra
nop
ENDFRAME(_CPU_ISR_Set_level)
#elif __mips == 1
/* MIPS ISA 1 ( R3000 ) */
/* _CPU_ISR_Get/Set_level are called as part of task mode manipulation. */
/* and are defined in C for the __mips == 1 */
#else
#error "__mips is set to 1 or 3"
#endif
/*
* _CPU_Context_save_fp_context
*
* This routine is responsible for saving the FP context
* at *fp_context_ptr. If the point to load the FP context
* from is changed then the pointer is modified by this routine.
*
* Sometimes a macro implementation of this is in cpu.h which dereferences
* the ** and a similarly named routine in this file is passed something
* like a (Context_Control_fp *). The general rule on making this decision
* is to avoid writing assembly language.
*/
/* void _CPU_Context_save_fp(
* void **fp_context_ptr
* );
*/
FRAME(_CPU_Context_save_fp,sp,0,ra)
.set noat
ld a1,(a0)
swc1 $f0,FP0_OFFSET*4(a1)
swc1 $f1,FP1_OFFSET*4(a1)
swc1 $f2,FP2_OFFSET*4(a1)
swc1 $f3,FP3_OFFSET*4(a1)
swc1 $f4,FP4_OFFSET*4(a1)
swc1 $f5,FP5_OFFSET*4(a1)
swc1 $f6,FP6_OFFSET*4(a1)
swc1 $f7,FP7_OFFSET*4(a1)
swc1 $f8,FP8_OFFSET*4(a1)
swc1 $f9,FP9_OFFSET*4(a1)
swc1 $f10,FP10_OFFSET*4(a1)
swc1 $f11,FP11_OFFSET*4(a1)
swc1 $f12,FP12_OFFSET*4(a1)
swc1 $f13,FP13_OFFSET*4(a1)
swc1 $f14,FP14_OFFSET*4(a1)
swc1 $f15,FP15_OFFSET*4(a1)
swc1 $f16,FP16_OFFSET*4(a1)
swc1 $f17,FP17_OFFSET*4(a1)
swc1 $f18,FP18_OFFSET*4(a1)
swc1 $f19,FP19_OFFSET*4(a1)
swc1 $f20,FP20_OFFSET*4(a1)
swc1 $f21,FP21_OFFSET*4(a1)
swc1 $f22,FP22_OFFSET*4(a1)
swc1 $f23,FP23_OFFSET*4(a1)
swc1 $f24,FP24_OFFSET*4(a1)
swc1 $f25,FP25_OFFSET*4(a1)
swc1 $f26,FP26_OFFSET*4(a1)
swc1 $f27,FP27_OFFSET*4(a1)
swc1 $f28,FP28_OFFSET*4(a1)
swc1 $f29,FP29_OFFSET*4(a1)
swc1 $f30,FP30_OFFSET*4(a1)
swc1 $f31,FP31_OFFSET*4(a1)
j ra
nop
.set at
ENDFRAME(_CPU_Context_save_fp)
/*
* _CPU_Context_restore_fp_context
*
* This routine is responsible for restoring the FP context
* at *fp_context_ptr. If the point to load the FP context
* from is changed then the pointer is modified by this routine.
*
* Sometimes a macro implementation of this is in cpu.h which dereferences
* the ** and a similarly named routine in this file is passed something
* like a (Context_Control_fp *). The general rule on making this decision
* is to avoid writing assembly language.
*/
/* void _CPU_Context_restore_fp(
* void **fp_context_ptr
* )
*/
FRAME(_CPU_Context_restore_fp,sp,0,ra)
.set noat
ld a1,(a0)
lwc1 $f0,FP0_OFFSET*4(a1)
lwc1 $f1,FP1_OFFSET*4(a1)
lwc1 $f2,FP2_OFFSET*4(a1)
lwc1 $f3,FP3_OFFSET*4(a1)
lwc1 $f4,FP4_OFFSET*4(a1)
lwc1 $f5,FP5_OFFSET*4(a1)
lwc1 $f6,FP6_OFFSET*4(a1)
lwc1 $f7,FP7_OFFSET*4(a1)
lwc1 $f8,FP8_OFFSET*4(a1)
lwc1 $f9,FP9_OFFSET*4(a1)
lwc1 $f10,FP10_OFFSET*4(a1)
lwc1 $f11,FP11_OFFSET*4(a1)
lwc1 $f12,FP12_OFFSET*4(a1)
lwc1 $f13,FP13_OFFSET*4(a1)
lwc1 $f14,FP14_OFFSET*4(a1)
lwc1 $f15,FP15_OFFSET*4(a1)
lwc1 $f16,FP16_OFFSET*4(a1)
lwc1 $f17,FP17_OFFSET*4(a1)
lwc1 $f18,FP18_OFFSET*4(a1)
lwc1 $f19,FP19_OFFSET*4(a1)
lwc1 $f20,FP20_OFFSET*4(a1)
lwc1 $f21,FP21_OFFSET*4(a1)
lwc1 $f22,FP22_OFFSET*4(a1)
lwc1 $f23,FP23_OFFSET*4(a1)
lwc1 $f24,FP24_OFFSET*4(a1)
lwc1 $f25,FP25_OFFSET*4(a1)
lwc1 $f26,FP26_OFFSET*4(a1)
lwc1 $f27,FP27_OFFSET*4(a1)
lwc1 $f28,FP28_OFFSET*4(a1)
lwc1 $f29,FP29_OFFSET*4(a1)
lwc1 $f30,FP30_OFFSET*4(a1)
lwc1 $f31,FP31_OFFSET*4(a1)
j ra
nop
.set at
ENDFRAME(_CPU_Context_restore_fp)
/* _CPU_Context_switch
*
* This routine performs a normal non-FP context switch.
*/
/* void _CPU_Context_switch(
* Context_Control *run,
* Context_Control *heir
* )
*/
#if __mips == 3
/* MIPS ISA Level 3 ( R4xxx ) */
FRAME(_CPU_Context_switch,sp,0,ra)
mfc0 t0,C0_SR
li t1,~SR_IE
sd t0,C0_SR_OFFSET*8(a0) /* save status register */
and t0,t1
mtc0 t0,C0_SR /* first disable ie bit (recommended) */
ori t0,SR_EXL|SR_IE /* enable exception level to disable interrupts */
mtc0 t0,C0_SR
sd ra,RA_OFFSET*8(a0) /* save current context */
sd sp,SP_OFFSET*8(a0)
sd fp,FP_OFFSET*8(a0)
sd s1,S1_OFFSET*8(a0)
sd s2,S2_OFFSET*8(a0)
sd s3,S3_OFFSET*8(a0)
sd s4,S4_OFFSET*8(a0)
sd s5,S5_OFFSET*8(a0)
sd s6,S6_OFFSET*8(a0)
sd s7,S7_OFFSET*8(a0)
dmfc0 t0,C0_EPC
sd t0,C0_EPC_OFFSET*8(a0)
_CPU_Context_switch_restore:
ld s0,S0_OFFSET*8(a1) /* restore context */
ld s1,S1_OFFSET*8(a1)
ld s2,S2_OFFSET*8(a1)
ld s3,S3_OFFSET*8(a1)
ld s4,S4_OFFSET*8(a1)
ld s5,S5_OFFSET*8(a1)
ld s6,S6_OFFSET*8(a1)
ld s7,S7_OFFSET*8(a1)
ld fp,FP_OFFSET*8(a1)
ld sp,SP_OFFSET*8(a1)
ld ra,RA_OFFSET*8(a1)
ld t0,C0_EPC_OFFSET*8(a1)
dmtc0 t0,C0_EPC
ld t0,C0_SR_OFFSET*8(a1)
andi t0,SR_EXL
bnez t0,_CPU_Context_1 /* set exception level from restore context */
li t0,~SR_EXL
mfc0 t1,C0_SR
nop
and t1,t0
mtc0 t1,C0_SR
_CPU_Context_1:
j ra
nop
ENDFRAME(_CPU_Context_switch)
#elif __mips == 1
/* MIPS ISA Level 1 ( R3000 ) */
FRAME(_CPU_Context_switch,sp,0,ra)
mfc0 t0,C0_SR
li t1,~SR_IEC
sw t0,C0_SR_OFFSET*4(a0) /* save status register */
and t0,t1
mtc0 t0,C0_SR /* first disable ie bit (recommended) */
sw ra,RA_OFFSET*4(a0) /* save current context */
sw sp,SP_OFFSET*4(a0)
sw fp,FP_OFFSET*4(a0)
sw s0,S0_OFFSET*4(a0)
sw s1,S1_OFFSET*4(a0)
sw s2,S2_OFFSET*4(a0)
sw s3,S3_OFFSET*4(a0)
sw s4,S4_OFFSET*4(a0)
sw s5,S5_OFFSET*4(a0)
sw s6,S6_OFFSET*4(a0)
sw s7,S7_OFFSET*4(a0)
mfc0 t0,C0_EPC
sw t0,C0_EPC_OFFSET*4(a0)
_CPU_Context_switch_restore:
lw s0,S0_OFFSET*4(a1) /* restore context */
lw s1,S1_OFFSET*4(a1)
lw s2,S2_OFFSET*4(a1)
lw s3,S3_OFFSET*4(a1)
lw s4,S4_OFFSET*4(a1)
lw s5,S5_OFFSET*4(a1)
lw s6,S6_OFFSET*4(a1)
lw s7,S7_OFFSET*4(a1)
lw fp,FP_OFFSET*4(a1)
lw sp,SP_OFFSET*4(a1)
lw ra,RA_OFFSET*4(a1)
lw t0,C0_EPC_OFFSET*4(a1)
mtc0 t0,C0_EPC
lw t0, C0_SR_OFFSET*4(a1)
andi t0,SR_IEC /* we know IEC=0, e.g. disabled */
beq t0,$0,_CPU_Context_1 /* set IEC level from restore context */
mfc0 t0,C0_SR
nop
or t0,SR_IEC /* new_sr = sr | SR_IEC */
mtc0 t0,C0_SR /* set with enabled */
_CPU_Context_1:
j ra
nop
ENDFRAME(_CPU_Context_switch)
#else
#error "__mips is not set to 1 or 3"
#endif
/*
* _CPU_Context_restore
*
* This routine is generally used only to restart self in an
* efficient manner. It may simply be a label in _CPU_Context_switch.
*
* NOTE: May be unnecessary to reload some registers.
*
* void _CPU_Context_restore(
* Context_Control *new_context
* );
*/
#if __mips == 3
FRAME(_CPU_Context_restore,sp,0,ra)
dadd a1,a0,zero
j _CPU_Context_switch_restore
nop
ENDFRAME(_CPU_Context_restore)
#elif __mips == 1
FRAME(_CPU_Context_restore,sp,0,ra)
add a1,a0,zero
j _CPU_Context_switch_restore
nop
ENDFRAME(_CPU_Context_restore)
#else
#error "__mips is not set to 1 or 3"
#endif
EXTERN(_ISR_Nest_level, SZ_INT)
EXTERN(_Thread_Dispatch_disable_level,SZ_INT)
EXTERN(_Context_Switch_necessary,SZ_INT)
EXTERN(_ISR_Signals_to_thread_executing,SZ_INT)
.extern _Thread_Dispatch
.extern _ISR_Vector_table
/* void __ISR_Handler()
*
* This routine provides the RTEMS interrupt management.
*
* void _ISR_Handler()
*
*
* This discussion ignores a lot of the ugly details in a real
* implementation such as saving enough registers/state to be
* able to do something real. Keep in mind that the goal is
* to invoke a user's ISR handler which is written in C and
* uses a certain set of registers.
*
* Also note that the exact order is to a large extent flexible.
* Hardware will dictate a sequence for a certain subset of
* _ISR_Handler while requirements for setting
*
* At entry to "common" _ISR_Handler, the vector number must be
* available. On some CPUs the hardware puts either the vector
* number or the offset into the vector table for this ISR in a
* known place. If the hardware does not give us this information,
* then the assembly portion of RTEMS for this port will contain
* a set of distinct interrupt entry points which somehow place
* the vector number in a known place (which is safe if another
* interrupt nests this one) and branches to _ISR_Handler.
*
*/
#if __mips == 3
/* ----------------------------------------------------------------------------- */
FRAME(_ISR_Handler,sp,0,ra)
.set noreorder
#if USE_IDTKIT
/* IDT/Kit incorrectly adds 4 to EPC before returning. This compensates */
lreg k0, R_EPC*R_SZ(sp)
daddiu k0,k0,-4
sreg k0, R_EPC*R_SZ(sp)
lreg k0, R_CAUSE*R_SZ(sp)
li k1, ~CAUSE_BD
and k0, k1
sreg k0, R_CAUSE*R_SZ(sp)
#endif
/* save registers not already saved by IDT/sim */
stackadd sp,sp,-EXCP_STACK_SIZE /* store ra on the stack */
sreg ra, R_RA*R_SZ(sp)
sreg v0, R_V0*R_SZ(sp)
sreg v1, R_V1*R_SZ(sp)
sreg a0, R_A0*R_SZ(sp)
sreg a1, R_A1*R_SZ(sp)
sreg a2, R_A2*R_SZ(sp)
sreg a3, R_A3*R_SZ(sp)
sreg t0, R_T0*R_SZ(sp)
sreg t1, R_T1*R_SZ(sp)
sreg t2, R_T2*R_SZ(sp)
sreg t3, R_T3*R_SZ(sp)
sreg t4, R_T4*R_SZ(sp)
sreg t5, R_T5*R_SZ(sp)
sreg t6, R_T6*R_SZ(sp)
sreg t7, R_T7*R_SZ(sp)
mflo k0
sreg t8, R_T8*R_SZ(sp)
sreg k0, R_MDLO*R_SZ(sp)
sreg t9, R_T9*R_SZ(sp)
mfhi k0
sreg gp, R_GP*R_SZ(sp)
sreg fp, R_FP*R_SZ(sp)
sreg k0, R_MDHI*R_SZ(sp)
.set noat
sreg AT, R_AT*R_SZ(sp)
.set at
stackadd sp,sp,-40 /* store ra on the stack */
sd ra,32(sp)
/* determine if an interrupt generated this exception */
mfc0 k0,C0_CAUSE
and k1,k0,CAUSE_EXCMASK
bnez k1,_ISR_Handler_prom_exit /* not an external interrupt,
pass exception to Monitor */
mfc0 k1,C0_SR
and k0,k1
and k0,CAUSE_IPMASK
beq k0,zero,_ISR_Handler_quick_exit /* external interrupt not
enabled, ignore */
nop
/*
* save some or all context on stack
* may need to save some special interrupt information for exit
*
* #if ( CPU_HAS_SOFTWARE_INTERRUPT_STACK == TRUE )
* if ( _ISR_Nest_level == 0 )
* switch to software interrupt stack
* #endif
*/
#if ( CPU_HAS_SOFTWARE_INTERRUPT_STACK == TRUE )
lint t0,_ISR_Nest_level
beq t0, zero, _ISR_Handler_1
nop
/* switch stacks */
_ISR_Handler_1:
#else
lint t0,_ISR_Nest_level
#endif
/*
* _ISR_Nest_level++;
*/
addi t0,t0,1
sint t0,_ISR_Nest_level
/*
* _Thread_Dispatch_disable_level++;
*/
lint t1,_Thread_Dispatch_disable_level
addi t1,t1,1
sint t1,_Thread_Dispatch_disable_level
#if 0
nop
j _ISR_Handler_4
nop
/*
* while ( interrupts_pending(cause_reg) ) {
* vector = BITFIELD_TO_INDEX(cause_reg);
* (*_ISR_Vector_table[ vector ])( vector );
* }
*/
_ISR_Handler_2:
/* software interrupt priorities can be applied here */
li t1,-1
/* convert bit field into interrupt index */
_ISR_Handler_3:
andi t2,t0,1
addi t1,1
beql t2,zero,_ISR_Handler_3
dsrl t0,1
li t1,7
dsll t1,3 /* convert index to byte offset (*8) */
la t3,_ISR_Vector_table
intadd t1,t3
lint t1,(t1)
jalr t1
nop
j _ISR_Handler_5
nop
_ISR_Handler_4:
mfc0 t0,C0_CAUSE
andi t0,CAUSE_IPMASK
bne t0,zero,_ISR_Handler_2
dsrl t0,t0,8
_ISR_Handler_5:
#else
nop
li t1,7
dsll t1,t1,SZ_INT_POW2
la t3,_ISR_Vector_table
intadd t1,t3
lint t1,(t1)
jalr t1
nop
#endif
/*
* --_ISR_Nest_level;
*/
lint t2,_ISR_Nest_level
addi t2,t2,-1
sint t2,_ISR_Nest_level
/*
* --_Thread_Dispatch_disable_level;
*/
lint t1,_Thread_Dispatch_disable_level
addi t1,t1,-1
sint t1,_Thread_Dispatch_disable_level
/*
* if ( _Thread_Dispatch_disable_level || _ISR_Nest_level )
* goto the label "exit interrupt (simple case)"
*/
or t0,t2,t1
bne t0,zero,_ISR_Handler_exit
nop
/*
* #if ( CPU_HAS_SOFTWARE_INTERRUPT_STACK == TRUE )
* restore stack
* #endif
*
* if ( !_Context_Switch_necessary && !_ISR_Signals_to_thread_executing )
* goto the label "exit interrupt (simple case)"
*/
lint t0,_Context_Switch_necessary
lint t1,_ISR_Signals_to_thread_executing
or t0,t0,t1
beq t0,zero,_ISR_Handler_exit
nop
/*
* call _Thread_Dispatch() or prepare to return to _ISR_Dispatch
*/
jal _Thread_Dispatch
nop
/*
* prepare to get out of interrupt
* return from interrupt (maybe to _ISR_Dispatch)
*
* LABEL "exit interrupt (simple case):
* prepare to get out of interrupt
* return from interrupt
*/
_ISR_Handler_exit:
ld ra,32(sp)
stackadd sp,sp,40
/* restore interrupt context from stack */
lreg k0, R_MDLO*R_SZ(sp)
mtlo k0
lreg k0, R_MDHI*R_SZ(sp)
lreg a2, R_A2*R_SZ(sp)
mthi k0
lreg a3, R_A3*R_SZ(sp)
lreg t0, R_T0*R_SZ(sp)
lreg t1, R_T1*R_SZ(sp)
lreg t2, R_T2*R_SZ(sp)
lreg t3, R_T3*R_SZ(sp)
lreg t4, R_T4*R_SZ(sp)
lreg t5, R_T5*R_SZ(sp)
lreg t6, R_T6*R_SZ(sp)
lreg t7, R_T7*R_SZ(sp)
lreg t8, R_T8*R_SZ(sp)
lreg t9, R_T9*R_SZ(sp)
lreg gp, R_GP*R_SZ(sp)
lreg fp, R_FP*R_SZ(sp)
lreg ra, R_RA*R_SZ(sp)
lreg a0, R_A0*R_SZ(sp)
lreg a1, R_A1*R_SZ(sp)
lreg v1, R_V1*R_SZ(sp)
lreg v0, R_V0*R_SZ(sp)
.set noat
lreg AT, R_AT*R_SZ(sp)
.set at
stackadd sp,sp,EXCP_STACK_SIZE /* store ra on the stack */
#if USE_IDTKIT
/* we handled exception, so return non-zero value */
li v0,1
#endif
_ISR_Handler_quick_exit:
#ifdef USE_IDTKIT
j ra
#else
eret
#endif
nop
_ISR_Handler_prom_exit:
#if __mips == 1
la k0, (R_VEC+((48)*8))
#endif
#if __mips == 3
la k0, (R_VEC+((112)*8)) /* R4000 Sim's location is different */
#endif
j k0
nop
.set reorder
ENDFRAME(_ISR_Handler)
/* ---------------------------------------------------------------------- */
#elif __mips == 1
/* MIPS ISA Level 1 */
FRAME(_ISR_Handler,sp,0,ra)
.set noreorder
/* Q: _ISR_Handler, not using IDT/SIM ...save extra regs? */
addiu sp,sp,-EXCP_STACK_SIZE /* wastes alot of stack space for context?? */
sw ra, R_RA*R_SZ(sp) /* store ra on the stack */
sw v0, R_V0*R_SZ(sp)
sw v1, R_V1*R_SZ(sp)
sw a0, R_A0*R_SZ(sp)
sw a1, R_A1*R_SZ(sp)
sw a2, R_A2*R_SZ(sp)
sw a3, R_A3*R_SZ(sp)
sw t0, R_T0*R_SZ(sp)
sw t1, R_T1*R_SZ(sp)
sw t2, R_T2*R_SZ(sp)
sw t3, R_T3*R_SZ(sp)
sw t4, R_T4*R_SZ(sp)
sw t5, R_T5*R_SZ(sp)
sw t6, R_T6*R_SZ(sp)
sw t7, R_T7*R_SZ(sp)
mflo k0
sw t8, R_T8*R_SZ(sp)
sw k0, R_MDLO*R_SZ(sp)
sw t9, R_T9*R_SZ(sp)
mfhi k0
sw gp, R_GP*R_SZ(sp)
sw fp, R_FP*R_SZ(sp)
sw k0, R_MDHI*R_SZ(sp)
.set noat
sw AT, R_AT*R_SZ(sp)
.set at
/* Q: Why hardcode -40 for stack add??? */
/* This needs to be figured out.........*/
addiu sp,sp,-40
sw ra,32(sp) /* store ra on the stack */
/* determine if an interrupt generated this exception */
mfc0 k0,C0_CAUSE
and k1,k0,CAUSE_EXCMASK
beq k1, 0, _ISR_Handler_1
nop
_ISR_Handler_Exception:
nop
b _ISR_Handler_Exception /* Jump to the exception code */
nop
_ISR_Handler_1:
mfc0 k1,C0_SR
and k0,k1
and k0,CAUSE_IPMASK
beq k0,zero,_ISR_Handler_exit /* external interrupt not enabled, ignore */
/* but if it's not an exception or an interrupt,
/* Then where did it come from??? */
nop
/*
* save some or all context on stack
* may need to save some special interrupt information for exit
*
* #if ( CPU_HAS_SOFTWARE_INTERRUPT_STACK == TRUE )
* if ( _ISR_Nest_level == 0 )
* switch to software interrupt stack
* #endif
*/
/*
* _ISR_Nest_level++;
*/
lw t0,_ISR_Nest_level
addi t0,t0,1
sw t0,_ISR_Nest_level
/*
* _Thread_Dispatch_disable_level++;
*/
lw t1,_Thread_Dispatch_disable_level
addi t1,t1,1
sw t1,_Thread_Dispatch_disable_level
/*
* while ( interrupts_pending(cause_reg) ) {
* vector = BITFIELD_TO_INDEX(cause_reg);
* (*_ISR_Vector_table[ vector ])( vector );
* }
*/
/* k0 has the SR interrupt bits */
la t3, _ISR_Vector_table
/* The bits you look at can be prioritized here just by */
/* changing what bit is looked at. I.E. SR_IBITx */
/* This code might become a loop, servicing all ints before returning.. */
/* Right now, it will go thru the whole list once */
_ISR_check_bit_0:
and k1, k0, SR_IBIT1
beq k1, zero, _ISR_check_bit_1
nop
li t1, ISR_VEC_SIZE*0
add t3, t1
jal t3
nop
_ISR_check_bit_1:
and k1, k0, SR_IBIT2
beq k1, zero, _ISR_check_bit_2
nop
li t1, ISR_VEC_SIZE*1
add t3, t1
jal t3
nop
_ISR_check_bit_2:
and k1, k0, SR_IBIT3
beq k1, zero, _ISR_check_bit_3
nop
li t1, ISR_VEC_SIZE*2
add t3, t1
jal t3
nop
_ISR_check_bit_3:
and k1, k0, SR_IBIT4
beq k1, zero, _ISR_check_bit_4
nop
li t1, ISR_VEC_SIZE*3
add t3, t1
jal t3
nop
_ISR_check_bit_4:
and k1, k0, SR_IBIT5
beq k1, zero, _ISR_check_bit_5
nop
li t1, ISR_VEC_SIZE*4
add t3, t1
jal t3
nop
_ISR_check_bit_5:
and k1, k0, SR_IBIT6
beq k1, zero, _ISR_check_bit_6
nop
li t1, ISR_VEC_SIZE*5
add t3, t1
jal t3
nop
_ISR_check_bit_6:
and k1, k0, SR_IBIT7
beq k1, zero, _ISR_check_bit_7
nop
li t1, ISR_VEC_SIZE*6
add t3, t1
jal t3
nop
_ISR_check_bit_7:
and k1, k0, SR_IBIT8
beq k1, zero, _ISR_exit_int_check
nop
li t1, ISR_VEC_SIZE*7
add t3, t1
jal t3
nop
_ISR_exit_int_check:
/*
* --_ISR_Nest_level;
*/
lw t2,_ISR_Nest_level
addi t2,t2,-1
sw t2,_ISR_Nest_level
/*
* --_Thread_Dispatch_disable_level;
*/
lw t1,_Thread_Dispatch_disable_level
addi t1,t1,-1
sw t1,_Thread_Dispatch_disable_level
/*
* if ( _Thread_Dispatch_disable_level || _ISR_Nest_level )
* goto the label "exit interrupt (simple case)"
*/
or t0,t2,t1
bne t0,zero,_ISR_Handler_exit
nop
/*
* #if ( CPU_HAS_SOFTWARE_INTERRUPT_STACK == TRUE )
* restore stack
* #endif
*
* if ( !_Context_Switch_necessary && !_ISR_Signals_to_thread_executing )
* goto the label "exit interrupt (simple case)"
*/
lw t0,_Context_Switch_necessary
lw t1,_ISR_Signals_to_thread_executing
or t0,t0,t1
beq t0,zero,_ISR_Handler_exit
nop
/*
* call _Thread_Dispatch() or prepare to return to _ISR_Dispatch
*/
jal _Thread_Dispatch
nop
/*
* prepare to get out of interrupt
* return from interrupt (maybe to _ISR_Dispatch)
*
* LABEL "exit interrupt (simple case):
* prepare to get out of interrupt
* return from interrupt
*/
_ISR_Handler_exit:
ld ra,32(sp)
addiu sp,sp,40 /* Q: Again with the 40...Is this needed? */
/* restore interrupt context from stack */
lw k0, R_MDLO*R_SZ(sp)
mtlo k0
lw k0, R_MDHI*R_SZ(sp)
lw a2, R_A2*R_SZ(sp)
mthi k0
lw a3, R_A3*R_SZ(sp)
lw t0, R_T0*R_SZ(sp)
lw t1, R_T1*R_SZ(sp)
lw t2, R_T2*R_SZ(sp)
lw t3, R_T3*R_SZ(sp)
lw t4, R_T4*R_SZ(sp)
lw t5, R_T5*R_SZ(sp)
lw t6, R_T6*R_SZ(sp)
lw t7, R_T7*R_SZ(sp)
lw t8, R_T8*R_SZ(sp)
lw t9, R_T9*R_SZ(sp)
lw gp, R_GP*R_SZ(sp)
lw fp, R_FP*R_SZ(sp)
lw ra, R_RA*R_SZ(sp)
lw a0, R_A0*R_SZ(sp)
lw a1, R_A1*R_SZ(sp)
lw v1, R_V1*R_SZ(sp)
lw v0, R_V0*R_SZ(sp)
.set noat
lw AT, R_AT*R_SZ(sp)
.set at
addiu sp,sp,EXCP_STACK_SIZE
rfe /* Might not need to do RFE here... */
j ra
nop
.set reorder
ENDFRAME(_ISR_Handler)
#else
#error "__mips is not set to 1 or 3 "
#endif
FRAME(mips_break,sp,0,ra)
#if 1
break 0x0
j mips_break
#else
j ra
#endif
nop
ENDFRAME(mips_break)
