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/*=============================================================================
//
//      vectors.S
//
//      SPARClite vectors and bootup code
//
//=============================================================================
// ####ECOSGPLCOPYRIGHTBEGIN####                                            
// -------------------------------------------                              
// This file is part of eCos, the Embedded Configurable Operating System.   
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under    
// the terms of the GNU General Public License as published by the Free     
// Software Foundation; either version 2 or (at your option) any later      
// version.                                                                 
//
// eCos is distributed in the hope that it will be useful, but WITHOUT      
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or    
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License    
// for more details.                                                        
//
// You should have received a copy of the GNU General Public License        
// along with eCos; if not, write to the Free Software Foundation, Inc.,    
// 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.            
//
// As a special exception, if other files instantiate templates or use      
// macros or inline functions from this file, or you compile this file      
// and link it with other works to produce a work based on this file,       
// this file does not by itself cause the resulting work to be covered by   
// the GNU General Public License. However the source code for this file    
// must still be made available in accordance with section (3) of the GNU   
// General Public License v2.                                               
//
// This exception does not invalidate any other reasons why a work based    
// on this file might be covered by the GNU General Public License.         
// -------------------------------------------                              
// ####ECOSGPLCOPYRIGHTEND####                                              
//=============================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):   hmt
// Contributors:hmt
// Date:        1998-12-15
// Purpose:     SPARClite vector code
// Description: This file contains the code which hangs off SPARClite vectors
//              including reset; it handles register under/overflow as well
//              as bootup, anything else is deferred to the default interrupt
//              or exception vsrs respectively.  See vec_[ix]vsr.S ...
//
//####DESCRIPTIONEND####
//
//===========================================================================*/

!-----------------------------------------------------------------------------
        
//      .file   "vectors.S"

!-----------------------------------------------------------------------------
                
#include <pkgconf/system.h>     
#include <pkgconf/hal.h>

#include <pkgconf/hal_sparclite.h>
#include CYGBLD_HAL_PLATFORM_H          // Platform config file

#ifdef CYGPKG_KERNEL
# include <pkgconf/kernel.h>
#else
# undef CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK
# undef CYGFUN_HAL_COMMON_KERNEL_SUPPORT
#endif
                        
#if defined( CYGPKG_HAL_SPARCLITE_SIM ) || \
    defined( CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK )
#define BOOTUPSTACK_IS_INTERRUPTSTACK
#endif
        
//#define CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING

#ifndef CYGHWR_HAL_SPARCLITE_HAS_ASR17
#ifndef CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
#error Single Vector Trapping (SVT) demands ASR17 
#endif
#endif
        
#ifdef CYG_HAL_STARTUP_ROM
# ifndef CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING

! ROM startup and Single Vector Trapping demands a copy to RAM.
! Otherwise it may be configured in, but it is not required.
        
#  ifndef CYGIMP_HAL_SPARCLITE_COPY_VECTORS_TO_RAM
#   define CYGIMP_HAL_SPARCLITE_COPY_VECTORS_TO_RAM
#  endif

# endif
#endif

!------------------------------------------------------------------------

#include <cyg/hal/vectors.h>

#define DELAYS_AFTER_WRPSR_SAME_WINDOW
#define DELAYS_AFTER_WRWIM

!------------------------------------------------------------------------

#ifdef CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING

        .macro  VECTOR_EXCEPTION
        .p2align 4
        rd      %tbr, %l3
        rd      %psr, %l0
        ba      __entry_exception
         and    %l3, TT_MASK, %l4
        .endm
        
        .macro  VECTOR_INTERRUPT level
        .p2align 4
        rd      %psr, %l0
        mov     \level << 2, %l5
        ba      __entry_interrupt
         mov    \level << 4, %l4
        .endm
        
        .macro  VECTOR_CODE_WIM name
        .p2align 4
        ba      __entry_\name
         rd     %wim, %l0
        .endm
        
#endif // CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING

!------------------------------------------------------------------------
! The start of the code; this is the entry point:
        
        .section ".vectors","ax"

        .global rom_vectors
rom_vectors:
        .global reset_vector
reset_vector:   
        ! this code goes to the real reset handler, it will be
        ! overwritten by the start of vectoring handler...
        b       genuine_reset
        nop
        ! usually drop through to:
#ifdef CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
        ba      __entry_exception       ! reset becomes an exception
         and    %l3, TT_MASK, %l4       ! once we are running
        
        VECTOR_EXCEPTION                !   1
        VECTOR_EXCEPTION                !   2
        VECTOR_EXCEPTION                !   3
        VECTOR_EXCEPTION                !   4
        
        VECTOR_CODE_WIM wover           !   5 window overflow
        VECTOR_CODE_WIM wunder          !   6 window underflow
        VECTOR_EXCEPTION                !   7
        VECTOR_EXCEPTION                !   8
        VECTOR_EXCEPTION                !   9

        VECTOR_EXCEPTION                !  10
        VECTOR_EXCEPTION                !  11
        VECTOR_EXCEPTION                !  12
        VECTOR_EXCEPTION                !  13
        VECTOR_EXCEPTION                !  14
        
        VECTOR_EXCEPTION                !  15
        VECTOR_EXCEPTION                !  16
        VECTOR_INTERRUPT  1             !  17 interrupt_level_1
        VECTOR_INTERRUPT  2             !  18 interrupt_level_2
        VECTOR_INTERRUPT  3             !  19 interrupt_level_3
        
        VECTOR_INTERRUPT  4             !  20 interrupt_level_4
        VECTOR_INTERRUPT  5             !  21 interrupt_level_5
        VECTOR_INTERRUPT  6             !  22 interrupt_level_6
        VECTOR_INTERRUPT  7             !  23 interrupt_level_7
        VECTOR_INTERRUPT  8             !  24 interrupt_level_8
        
        VECTOR_INTERRUPT  9             !  25 interrupt_level_9
        VECTOR_INTERRUPT 10             !  26 interrupt_level_10
        VECTOR_INTERRUPT 11             !  27 interrupt_level_11
        VECTOR_INTERRUPT 12             !  28 interrupt_level_12
        VECTOR_INTERRUPT 13             !  29 interrupt_level_13
        
        VECTOR_INTERRUPT 14             !  30 interrupt_level_14
        VECTOR_INTERRUPT 15             !  31 interrupt_level_15
        VECTOR_EXCEPTION                !  32
        VECTOR_EXCEPTION                !  33
        VECTOR_EXCEPTION                !  34

        VECTOR_EXCEPTION                !  35
        VECTOR_EXCEPTION                !  36
        VECTOR_EXCEPTION                !  37
        VECTOR_EXCEPTION                !  38
        VECTOR_EXCEPTION                !  39
        
        .rept 216                       ! 40-255 is 216 of them
        VECTOR_EXCEPTION                ! whichever
        .endr
#endif // CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING

#ifndef CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
real_vector:
        ! here,locals have been set up as follows:
        ! %l0 = psr
        ! %l1 = pc      
        ! %l2 = npc
        ! %l3 = tbr
        and     %l3, TT_IS_INTR_MASK, %l4
        cmp     %l4, TT_IS_INTR_VALUE
        bne     not_an_interrupt        ! delay slot does not matter
        ! here be the pre-vector interrupt handler
interrupt:
        and     %l3, 0x0f0, %l4         ! get an interrupt number out
        srl     %l4, 2, %l5             ! to a word address offset
#endif // !CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
__entry_interrupt:
        sethi   %hi(hal_vsr_table), %l6
        or      %l6, %lo(hal_vsr_table), %l6
        ld      [ %l6 + %l5 ], %l6      ! get vector in %l6
        jmp     %l6                     ! and go there
        srl     %l4, 4, %l3             ! vector number into %l3: so that
                                        ! interrupts and exceptions/traps
                                        ! have the same API to VSRs

#ifndef CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
not_an_interrupt:
        and     %l3, TT_MASK, %l4
        cmp     %l4, (TRAP_WUNDER << TT_SHL)

        bne,a   not_window_underflow
        cmp     %l4, (TRAP_WOVER << TT_SHL)     ! (if taken)

        ! here be the window underflow handler:
window_underflow:
        ! CWP is trap handler
        ! CWP + 1 is trapped RESTORE instruction
        ! CWP + 2 is invalid context which must be restored
        ! CWP + 3 is next invalid context

        wr      %l0, %psr               ! restore the condition flags
                                        ! (CWP is unchanged)
        ! the following instructions delay enough; no need for NOPs
        rd      %wim, %l0               ! get the wim
#endif // !CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
__entry_wunder: 
        sll     %l0, 1, %l3             ! Rotate wim left
        srl     %l0, __WINSIZE-1, %l0
        wr      %l0, %l3, %wim          ! Install the new wim

#ifdef DELAYS_AFTER_WRWIM
        nop                             ! are these delays needed?
        nop                             ! (following restore uses wim)
        nop
#endif
        restore                         ! Users window
        restore                         ! Her callers window (now valid)
        
        ldd     [%sp + 0 * 4], %l0      ! restore L & I registers
        ldd     [%sp + 2 * 4], %l2
        ldd     [%sp + 4 * 4], %l4
        ldd     [%sp + 6 * 4], %l6

        ldd     [%sp + 8 * 4], %i0
        ldd     [%sp + 10 * 4], %i2
        ldd     [%sp + 12 * 4], %i4
        ldd     [%sp + 14 * 4], %i6

        save                            ! Back to trap window
        save    

        jmp     %l1
        rett    %l2

#ifndef CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
not_window_underflow:
        bne,a   not_window_overflow
        srl     %l4, 4, %l4             ! (if taken)

        ! here be the window overflow handler:
window_overflow:
        ! CWP + 1 is caller whose SAVE bounced
        ! CWP is trap handler = invalid window
        ! CWP - 1 is next invalid window which needs to be saved

        wr      %l0, %psr               ! restore the condition flags
                                        ! (CWP is unchanged)
        ! the following instructions delay enough; no need for NOPs
        rd      %wim, %l0
#endif // !CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
__entry_wover:  
        mov     %g1, %l3                ! Save g1, we use it to hold the wim
        srl     %l0, 1, %g1             ! Rotate wim right
        sll     %l0, __WINSIZE-1, %l0
        or      %l0, %g1, %g1

        save                            ! Slip into next window
        mov     %g1, %wim               ! Install the new wim
                                        ! (invalidates current window!)

        std     %l0, [%sp + 0 * 4]      ! save L & I registers
        std     %l2, [%sp + 2 * 4]
        std     %l4, [%sp + 4 * 4]
        std     %l6, [%sp + 6 * 4]

        std     %i0, [%sp + 8 * 4]
        std     %i2, [%sp + 10 * 4]
        std     %i4, [%sp + 12 * 4]
        std     %i6, [%sp + 14 * 4]

        restore                         ! Go back to trap window.
        mov     %l3, %g1                ! Restore %g1

        jmpl    %l1,  %g0
        rett    %l2

#ifdef CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
        // ADDITIONAL code to provide an entry point:
__entry_exception:
        srl     %l4, 4, %l4
#endif // CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
not_window_overflow:
        ! from here on in, %l4 is the trap number in clear
        cmp     %l4, 128 
        bge     1f
        mov     0, %l5                  ! offset 0 for user traps

        cmp     %l4, 36                 ! coprocessor special case
        beq     1f
        mov     4, %l5                  ! ...treated as FP, code 4

        cmp     %l4, 10
        bge     1f
        mov     10, %l5                 ! offset 10 for "others"

        ! if we are here, the trap number is 1-9 inclusive
        ! so put it in %l5 and drop through...
        mov     %l4, %l5
1:      
        or      %l5, 16, %l5            ! offset into table is 16... for traps.
        sll     %l5,  2, %l5            ! to a word address offset
        sethi   %hi(hal_vsr_table), %l6
        or      %l6, %lo(hal_vsr_table), %l6
        ld      [ %l6 + %l5 ], %l6      ! get vector in %l6
        jmp     %l6                     ! and go there
        srl     %l5, 2, %l3             ! vector number into %l3: so that
                                        ! interrupts and exceptions/traps
                                        ! have the same API to VSRs
        ! NB that~s eCos vector number not TRAP number above.
        
        ! and that is the end of the pre-vector trap handler    

        .global rom_vectors_end
rom_vectors_end:
                
        ! these instructions are copied into the reset vector
        ! after startup to _not_ branch to the genuine_reset code below
real_vector_instructions:
        rd      %tbr, %l3
        rd      %psr, %l0



        ! genuine reset code called from time zero:
genuine_reset:                          ! set psr, mask interrupts & traps
        wr      %g0, 0xfc0 + __WIN_INIT, %psr
        nop                             ! mode = prevMode = S, CWP=7
        nop
        nop
        wr      %g0, 0, %wim            ! No invalid windows (yet)
        nop
        nop
        nop

        sethi   %hi(reset_vector), %g1
        andn    %g1, 0xfff, %g1         ! should not be needed
        wr      %g1, %tbr               ! Traps are at reset_vector
        nop
        nop
        nop
#ifdef CYGHWR_HAL_SPARCLITE_HAS_ASR17
#ifdef CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
        wr      %g0, 0, %asr17          ! Multiple vector trapping
#else
        wr      %g0, 1, %asr17          ! Single vector trapping
#endif // !CYGHWR_HAL_SPARCLITE_MULTIPLE_VECTOR_TRAPPING
#endif // CYGHWR_HAL_SPARCLITE_HAS_ASR17
        nop
        nop
        nop

// INCLUDE PLATFORM BOOT

// This should set up RAM and caches, and calm down any external interrupt
// sources.  Also copy two instructions from real_vector_instructions
// into reset_vector, then invalidate the instruction cache.
        
#include <cyg/hal/halboot.si>
        
// halboot.si returns with %sp all set, in sleb versions.
// (though we override if there is an interrupt stack)

        led     0x80
                
        ! now set up a stack and initial frame linkage
        ! so as to be able to make C function calls:
        ! current window is 7, the highest, so we store a
        ! saved frame thingy that refers to itself in the stack,
        ! then another which is valid and drop into main from there.

#ifdef BOOTUPSTACK_IS_INTERRUPTSTACK
        sethi   %hi(cyg_interrupt_stack), %i6
        or      %i6, %lo(cyg_interrupt_stack), %i6
#endif  
        andn    %i6, 7, %i6             ! round fp down to double alignment
        mov     0, %i7                  ! null return address
        sethi   %hi(0xb51ac000), %i0    ! "BStac" pattern
        or      %i0, 24, %i0    
        or      %i0, 1, %i1
        or      %i0, 2, %i2
        or      %i0, 3, %i3
        or      %i0, 4, %i4
        or      %i0, 5, %i5

        sethi   %hi(0xb51ac000), %l0    ! "BStac" pattern
        or      %l0, 16, %l0    
        or      %l0, 1, %l1
        or      %l0, 2, %l2
        or      %l0, 3, %l3
        or      %l0, 4, %l4
        or      %l0, 5, %l5
        or      %l0, 6, %l6
        or      %l0, 7, %l7
        
        sub     %fp, 16 * 4, %sp        ! Stack pointer

        led     0x90
        
        std     %l0, [%sp + 0 * 4]      ! save L & I registers
        std     %l2, [%sp + 2 * 4]      ! into new stack frame
        std     %l4, [%sp + 4 * 4]
        std     %l6, [%sp + 6 * 4]

        led     0x91
        
        std     %i0, [%sp + 8 * 4]
        std     %i2, [%sp + 10 * 4]
        std     %i4, [%sp + 12 * 4]
        std     %i6, [%sp + 14 * 4]
        
        led     0x92
        
        sethi   %hi(0xb0010000), %o0    ! "Boot" pattern
        or      %o0, 8, %o0     
        or      %o0, 1, %o1
        or      %o0, 2, %o2
        or      %o0, 3, %o3
        or      %o0, 4, %o4
        or      %o0, 5, %o5

        led     0x98
                
        wr      %g0, __WIM_INIT, %wim   ! Window 7 (current) is invalid
        nop
        nop
        nop
        
        led     0x99
        
        sethi   %hi(0xb0010000), %g1    ! "Boot" pattern
        or      %g1, 2, %g2
        or      %g1, 3, %g3
        or      %g1, 4, %g4
        or      %g1, 5, %g5
        or      %g1, 6, %g6
        or      %g1, 7, %g7
        or      %g1, 1, %g1

        led     0xa0
        
        wr      %g0, 0xfe0 + __WIN_INIT, %psr
        nop                             ! Enable traps:             
        nop                             ! set psr, _do_ mask interrupts
        nop                             ! mode = prevMode = S, CWP=7

        led     0xb0

        ! now we can start calling out and running C code!
        .extern cyg_hal_start   
        call    cyg_hal_start           ! puts return address in %o7
        or      %g1, 1, %g1
        
loop_forever:
        ta      1
        b       loop_forever            ! if it returns
        nop

        
!---------------------------------------------------------------------------
! hal_vsr_table...

        .section ".data"
        .balign 4
        .global hal_vsr_table
hal_vsr_table:
        .rept 16
        .word hal_default_interrupt_vsr
        .endr
        .rept 11
        .word hal_default_exception_vsr
        .endr

!---------------------------------------------------------------------------
! Bootup stack (only needed explicitly in sim)
        
#ifdef BOOTUPSTACK_IS_INTERRUPTSTACK
        .section ".bss"

#ifndef CYGNUM_HAL_COMMON_INTERRUPTS_STACK_SIZE
#define CYGNUM_HAL_COMMON_INTERRUPTS_STACK_SIZE 4096
#endif
        .balign 16
        .global cyg_interrupt_stack_base
cyg_interrupt_stack_base:
        .rept CYGNUM_HAL_COMMON_INTERRUPTS_STACK_SIZE
        .byte 0
        .endr
        .balign 16
        .global cyg_interrupt_stack
cyg_interrupt_stack:
        .long   0,0,0,0,0,0,0,0         ! here be secret state stored
#endif

!------------------------------------------------------------------------
! Define a section that reserves space at the start of RAM for the
! vectors to be copied into, for ROM start only.
        
        .section ".ram_vectors","awx",@nobits
#ifdef CYGIMP_HAL_SPARCLITE_COPY_VECTORS_TO_RAM
        ! need a space at base of RAM for copied vector/trampoline code
        .align 0x1000
        .space 8                        ! for fencepost errors
        .space (rom_vectors_end - rom_vectors)
#endif // CYGIMP_HAL_SPARCLITE_COPY_VECTORS_TO_RAM

!------------------------------------------------------------------------
! end of vectors.S