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https://github.com/AsahiLinux/u-boot
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e4cc71aa44
Add Nios GDB/JTAG Console support: - Add stubs to support gdb via JTAG. - Add support for console over JTAG. - Minor cleanup.
582 lines
14 KiB
ArmAsm
582 lines
14 KiB
ArmAsm
/*
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* (C) Copyright 2003, Psyent Corporation <www.psyent.com>
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* Scott McNutt <smcnutt@psyent.com>
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <config.h>
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/*************************************************************************
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* Register window underflow
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*
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* The register window underflow exception occurs whenever the lowest
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* valid register window is in use (CWP=LO_LIMIT) and a save instruction
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* is issued. The save moves CWP below LO_LIMIT, %sp is set as normal,
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* then the exception is generated prior to executing the instruction
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* after the save.
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************************************************************************/
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.text
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.global _cwp_lolimit
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.align 4
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_cwp_lolimit:
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/* Sixteen words are always allocated by the compiler in every
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* procedure's stack frame, always starting at %sp, for saving
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* 'in' and 'local' registers on a window overflow.
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*
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* Save the 'global' and 'in' regs on stack. They are restored
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* at cwp = HI_LIMIT. The 'local' regs aren't in-use at this point.
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*/
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sts [%sp,0], %g0 /* Save 'global' regs*/
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sts [%sp,1], %g1
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sts [%sp,2], %g2
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sts [%sp,3], %g3
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sts [%sp,4], %g4
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sts [%sp,5], %g5
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sts [%sp,6], %g6
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sts [%sp,7], %g7
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sts [%sp,8], %i0 /* Save 'in' regs */
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sts [%sp,9], %i1
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sts [%sp,10], %i2
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sts [%sp,11], %i3
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sts [%sp,12], %i4
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sts [%sp,13], %i5
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sts [%sp,14], %i6
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sts [%sp,15], %i7
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/* Save current %sp and return address in a global so they are
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* available at cwp = HI_LIMIT ... where the 'global'/'in' regs
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* are restored. NOTE: %sp changes with cwp.
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*/
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mov %g7, %o7
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mov %g6, %sp
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/* Get LO_LIMIT/HI_LIMIT to know where to start & stop. Note: in
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* the underflow exception, cwp is __NOT__ guaranteed to be zero.
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* If the OCI debug module is enabled the reset value for LO_LIMIT
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* is 2, not 1 -- so cwp can be 1 or 0.
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*/
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pfx 2 /* WVALID */
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rdctl %g1
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mov %g2, %g1
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pfx 0
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and %g1, 0x1f /* g1 <- LO_LIMIT */
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lsri %g2, 5
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pfx 0
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and %g2,0x1f /* g2 <- HI_LIMIT */
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/* Set istatus so cwp = HI_LIMIT after tret
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*/
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movi %g5, 0x1f
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lsli %g5, 4
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not %g5 /* mask to clr cwp */
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pfx 1 /* istatus */
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rdctl %g0
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and %g0, %g5 /* clear cwp field */
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mov %g4, %g2
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lsli %g4, 4
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or %g0, %g4 /* cwp = HI_LIMIT */
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pfx 1
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wrctl %g0 /* update istatus */
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/* Now move up the register file, saving as we go. When loop
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* is first entered, %g1 is at LO_LIMIT.
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*/
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0:
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restore /* cwp++ */
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sts [%sp,0], %l0 /* Save "local" regs*/
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sts [%sp,1], %l1
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sts [%sp,2], %l2
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sts [%sp,3], %l3
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sts [%sp,4], %l4
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sts [%sp,5], %l5
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sts [%sp,6], %l6
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sts [%sp,7], %l7
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sts [%sp,8], %i0 /* Save 'in' regs */
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sts [%sp,9], %i1
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sts [%sp,10], %i2
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sts [%sp,11], %i3
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sts [%sp,12], %i4
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sts [%sp,13], %i5
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sts [%sp,14], %i6
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sts [%sp,15], %i7
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cmp %g1, %g2 /* cwp == HI_LIMIT ? */
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skps cc_ne /* if so, we're done */
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br 1f
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nop /* delay slot */
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inc %g1 /* g1 <- cwp++ */
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br 0b
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nop /* delay slot */
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/* At this point cwp = HI_LIMIT, so the global/in regs that were
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* in place when the underflow occurred must be restored using
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* the original stack pointer (saved in g6).
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*/
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1:
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mov %o7, %g7 /* restore return addr */
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mov %sp, %g6 /* Restore original sp */
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lds %g0, [%sp,0] /* Restore 'global' regs*/
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lds %g1, [%sp,1]
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lds %g2, [%sp,2]
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lds %g3, [%sp,3]
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lds %g4, [%sp,4]
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lds %g5, [%sp,5]
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lds %g6, [%sp,6]
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lds %g7, [%sp,7]
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lds %i0, [%sp,8] /* Restore 'in' regs*/
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lds %i1, [%sp,9]
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lds %i2, [%sp,10]
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lds %i3, [%sp,11]
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lds %i4, [%sp,12]
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lds %i5, [%sp,13]
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lds %i6, [%sp,14]
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lds %i7, [%sp,15]
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tret %o7 /* All done */
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/*************************************************************************
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* Register window overflow
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*
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* The register window overflow exception occurs whenever the highest
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* valid register window is in use (cwp = HI_LIMIT) and a restore
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* instruction is issued. Control is transferred to the overflow handler
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* before the instruction following restore is executed.
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*
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* When a register window overflow exception is taken, the exception
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* handler sees cwp at HI_LIMIT.
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************************************************************************/
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.text
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.global _cwp_hilimit
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.align 4
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_cwp_hilimit:
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/* Save 'global'/'in' regs on the stack -- will restore when cwp
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* is at LO_LIMIT. Locals don't need saving as they are going away.
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*/
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sts [%sp,0], %g0 /* Save "global" regs*/
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sts [%sp,1], %g1
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sts [%sp,2], %g2
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sts [%sp,3], %g3
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sts [%sp,4], %g4
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sts [%sp,5], %g5
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sts [%sp,6], %g6
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sts [%sp,7], %g7
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sts [%sp,8], %i0 /* Save 'in' regs */
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sts [%sp,9], %i1
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sts [%sp,10], %i2
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sts [%sp,11], %i3
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sts [%sp,12], %i4
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sts [%sp,13], %i5
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sts [%sp,14], %i6
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sts [%sp,15], %i7
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/* The current %sp must be available in global to restore regs
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* saved on stack. Need return addr as well ;-)
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*/
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mov %g7, %o7
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mov %g6, %sp
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/* Get HI_LIMIT & LO_LIMIT
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*/
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pfx 2 /* WVALID */
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rdctl %g1
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mov %g2, %g1
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pfx 0
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and %g1, 0x1f /* g1 <- LO_LIMIT */
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lsri %g2, 5
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pfx 0
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and %g2,0x1f /* g2 <- HI_LIMIT */
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/* Set istatus so cwp = LO_LIMIT after tret
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*/
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movi %g5, 0x1f
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lsli %g5, 4
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not %g5 /* mask to clr cwp */
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pfx 1 /* istatus */
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rdctl %g0
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and %g0, %g5 /* clear cwp field */
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mov %g4, %g1 /* g4 <- LO_LIMIT */
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lsli %g4, 4
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or %g0, %g4 /* cwp = LO_LIMIT */
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pfx 1
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wrctl %g0 /* update istatus */
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/* Move to cwp = LO_LIMIT-1 and restore 'in' regs.
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*/
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subi %g4,(1 << 4) /* g4 <- LO_LIMIT - 1 */
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rdctl %g0
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and %g0, %g5 /* clear cwp field */
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or %g0, %g4 /* cwp = LO_LIMIT - 1 */
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wrctl %g0 /* update status */
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nop
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mov %sp, %g6 /* Restore sp */
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lds %i0, [%sp,8] /* Restore 'in' regs */
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lds %i1, [%sp,9]
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lds %i2, [%sp,10]
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lds %i3, [%sp,11]
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lds %i4, [%sp,12]
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lds %i5, [%sp,13]
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lds %i6, [%sp,14] /* sp in next window */
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lds %i7, [%sp,15]
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/* Starting at LO_LIMIT-1, move up the register file, restoring
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* along the way.
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*/
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0:
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restore /* cwp++ */
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lds %l0, [%sp,0] /* Restore 'local' regs*/
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lds %l1, [%sp,1]
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lds %l2, [%sp,2]
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lds %l3, [%sp,3]
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lds %l4, [%sp,4]
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lds %l5, [%sp,5]
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lds %l6, [%sp,6]
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lds %l7, [%sp,7]
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lds %i0, [%sp,8] /* Restore 'in' regs */
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lds %i1, [%sp,9]
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lds %i2, [%sp,10]
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lds %i3, [%sp,11]
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lds %i4, [%sp,12]
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lds %i5, [%sp,13]
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lds %i6, [%sp,14] /* sp in next window */
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lds %i7, [%sp,15]
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cmp %g1, %g2 /* cwp == HI_LIMIT ? */
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skps cc_ne /* if so, we're done */
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br 1f
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nop /* delay slot */
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inc %g1 /* cwp++ */
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br 0b
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nop /* delay slot */
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/* All windows have been updated at this point, but the globals
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* still need to be restored. Go to cwp = LO_LIMIT-1 to get
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* some registers to use.
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*/
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1:
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rdctl %g0
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and %g0, %g5 /* clear cwp field */
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or %g0, %g4 /* cwp = LO_LIMIT - 1 */
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wrctl %g0 /* update status */
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nop
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/* Now there are some registers available to use in restoring
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* the globals.
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*/
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mov %sp, %g6
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mov %o7, %g7
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lds %g0, [%sp,0] /* Restore "global" regs*/
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lds %g1, [%sp,1]
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lds %g2, [%sp,2]
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lds %g3, [%sp,3]
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lds %g4, [%sp,4]
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lds %g5, [%sp,5]
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lds %g6, [%sp,6]
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lds %g7, [%sp,7]
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/* The tret moves istatus -> status. istatus was already set for
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* cwp = LO_LIMIT.
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*/
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tret %o7 /* done */
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/*************************************************************************
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* Default exception handler
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*
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* The default handler passes control to external_interrupt(). So trap
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* or hardware interrupt hanlders can be installed using the familiar
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* irq_install_handler().
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*
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* Here, the stack is fixed-up and cwp is incremented prior to calling
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* external_interrupt(). This lets the underflow and overflow handlers
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* operate normally during the exception.
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************************************************************************/
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.text
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.global _def_xhandler
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.align 4
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_def_xhandler:
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/* Allocate some stack space: 16 words at %sp to accomodate
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* a reg window underflow, 8 words to save interrupted task's
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* 'out' regs (which are now the 'in' regs), 8 words to preserve
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* the 'global' regs and 3 words to save the return address,
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* status and istatus. istatus must be saved in the event an
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* underflow occurs in a dispatched handler. status is saved so
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* a handler can access it on stack.
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*/
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pfx %hi((16+16+3) * 4)
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subi %fp, %lo((16+16+3) * 4)
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mov %sp, %fp
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/* Save the 'global' regs and the interrupted task's 'out' regs
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* (our 'in' regs) along with the return addr, status & istatus.
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* First 16 words are for underflow exception.
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*/
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rdctl %l0 /* status */
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pfx 1 /* istatus */
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rdctl %l1
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sts [%sp,16+0], %g0 /* Save 'global' regs*/
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sts [%sp,16+1], %g1
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sts [%sp,16+2], %g2
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sts [%sp,16+3], %g3
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sts [%sp,16+4], %g4
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sts [%sp,16+5], %g5
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sts [%sp,16+6], %g6
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sts [%sp,16+7], %g7
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sts [%sp,16+8], %i0 /* Save 'in' regs */
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sts [%sp,16+9], %i1
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sts [%sp,16+10], %i2
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sts [%sp,16+11], %i3
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sts [%sp,16+12], %i4
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sts [%sp,16+13], %i5
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sts [%sp,16+14], %i6
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sts [%sp,16+15], %i7
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sts [%sp,16+16], %l0 /* status */
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sts [%sp,16+17], %l1 /* istatus */
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sts [%sp,16+18], %o7 /* return addr */
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/* Move to cwp+1 ... this guarantees cwp is at or above LO_LIMIT.
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* Need to set IPRI=3 and IE=1 to enable underflow exceptions.
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* NOTE: only the 'out' regs have been saved ... can't touch
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* the 'in' or 'local' here.
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*/
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restore /* cwp++ */
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rdctl %o0 /* o0 <- status */
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pfx %hi(0x7e00)
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movi %o1, %lo(0x7e00)
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not %o1
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and %o0, %o1 /* clear IPRI */
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pfx %hi(0x8600)
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movi %o1, %lo(0x8600)
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or %o0, %o1 /* IPRI=3, IE=1 */
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wrctl %o0 /* o0 -> status */
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nop
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/* It's ok to call a C routine now since cwp >= LO_LIMIT,
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* interrupt task's registers are/will be preserved, and
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* underflow exceptions can be handled.
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*/
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pfx %hi(external_interrupt@h)
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movi %o1, %lo(external_interrupt@h)
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pfx %xhi(external_interrupt@h)
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movhi %o1, %xlo(external_interrupt@h)
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bgen %o0, 4+2 /* 16 * 4 */
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add %o0, %sp /* Ptr to regs */
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call %o1
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nop
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/* Move back to the exception register window, restore the 'out'
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* registers, then return from exception.
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*/
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rdctl %o0 /* o0 <- status */
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subi %o0, 16
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wrctl %o0 /* cwp-- */
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nop
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mov %sp, %fp
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lds %g0, [%sp,16+0] /* Restore 'global' regs*/
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lds %g1, [%sp,16+1]
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lds %g2, [%sp,16+2]
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lds %g3, [%sp,16+3]
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lds %g4, [%sp,16+4]
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lds %g5, [%sp,16+5]
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lds %g6, [%sp,16+6]
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lds %g7, [%sp,16+7]
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lds %i0, [%sp,16+8] /* Restore 'in' regs*/
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lds %i1, [%sp,16+9]
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lds %i2, [%sp,16+10]
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lds %i3, [%sp,16+11]
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lds %i4, [%sp,16+12]
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lds %i5, [%sp,16+13]
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lds %i6, [%sp,16+14]
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lds %i7, [%sp,16+15]
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lds %l0, [%sp,16+16] /* status */
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lds %l1, [%sp,16+17] /* istatus */
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lds %o7, [%sp,16+18] /* return addr */
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pfx 1
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wrctl %l1 /* restore istatus */
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pfx %hi((16+16+3) * 4)
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addi %sp, %lo((16+16+3) * 4)
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mov %fp, %sp
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tret %o7 /* Done */
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/*************************************************************************
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* Timebase Timer Interrupt -- This has identical structure to above,
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* but calls timer_interrupt(). Doing it this way keeps things similar
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* to other architectures (e.g. ppc).
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************************************************************************/
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.text
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.global _timebase_int
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.align 4
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_timebase_int:
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/* Allocate stack space.
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*/
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pfx %hi((16+16+3) * 4)
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subi %fp, %lo((16+16+3) * 4)
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mov %sp, %fp
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/* Save the 'global' regs & 'out' regs (our 'in' regs)
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*/
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rdctl %l0 /* status */
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pfx 1 /* istatus */
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rdctl %l1
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sts [%sp,16+0], %g0 /* Save 'global' regs*/
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sts [%sp,16+1], %g1
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sts [%sp,16+2], %g2
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sts [%sp,16+3], %g3
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sts [%sp,16+4], %g4
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sts [%sp,16+5], %g5
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sts [%sp,16+6], %g6
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sts [%sp,16+7], %g7
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sts [%sp,16+8], %i0 /* Save 'in' regs */
|
|
sts [%sp,16+9], %i1
|
|
sts [%sp,16+10], %i2
|
|
sts [%sp,16+11], %i3
|
|
sts [%sp,16+12], %i4
|
|
sts [%sp,16+13], %i5
|
|
sts [%sp,16+14], %i6
|
|
sts [%sp,16+15], %i7
|
|
|
|
sts [%sp,16+16], %l0 /* status */
|
|
sts [%sp,16+17], %l1 /* istatus */
|
|
sts [%sp,16+18], %o7 /* return addr */
|
|
|
|
/* Move to cwp+1.
|
|
*/
|
|
restore /* cwp++ */
|
|
rdctl %o0 /* o0 <- status */
|
|
|
|
pfx %hi(0x7e00)
|
|
movi %o1, %lo(0x7e00)
|
|
not %o1
|
|
and %o0, %o1 /* clear IPRI */
|
|
|
|
pfx %hi(0x8600)
|
|
movi %o1, %lo(0x8600)
|
|
or %o0, %o1 /* IPRI=3, IE=1 */
|
|
|
|
wrctl %o0 /* o0 -> status */
|
|
nop
|
|
|
|
/* Call timer_interrupt()
|
|
*/
|
|
pfx %hi(timer_interrupt@h)
|
|
movi %o1, %lo(timer_interrupt@h)
|
|
pfx %xhi(timer_interrupt@h)
|
|
movhi %o1, %xlo(timer_interrupt@h)
|
|
bgen %o0, 4+2 /* 16 * 4 */
|
|
add %o0, %sp /* Ptr to regs */
|
|
call %o1
|
|
nop
|
|
|
|
/* Move back to the exception register window, restore the 'out'
|
|
* registers, then return from exception.
|
|
*/
|
|
rdctl %o0 /* o0 <- status */
|
|
subi %o0, 16
|
|
wrctl %o0 /* cwp-- */
|
|
nop
|
|
|
|
mov %sp, %fp
|
|
lds %g0, [%sp,16+0] /* Restore 'global' regs*/
|
|
lds %g1, [%sp,16+1]
|
|
lds %g2, [%sp,16+2]
|
|
lds %g3, [%sp,16+3]
|
|
lds %g4, [%sp,16+4]
|
|
lds %g5, [%sp,16+5]
|
|
lds %g6, [%sp,16+6]
|
|
lds %g7, [%sp,16+7]
|
|
|
|
lds %i0, [%sp,16+8] /* Restore 'in' regs*/
|
|
lds %i1, [%sp,16+9]
|
|
lds %i2, [%sp,16+10]
|
|
lds %i3, [%sp,16+11]
|
|
lds %i4, [%sp,16+12]
|
|
lds %i5, [%sp,16+13]
|
|
lds %i6, [%sp,16+14]
|
|
lds %i7, [%sp,16+15]
|
|
|
|
lds %l0, [%sp,16+16] /* status */
|
|
lds %l1, [%sp,16+17] /* istatus */
|
|
lds %o7, [%sp,16+18] /* return addr */
|
|
|
|
pfx 1
|
|
wrctl %l1 /* restore istatus */
|
|
|
|
pfx %hi((16+16+3) * 4)
|
|
addi %sp, %lo((16+16+3) * 4)
|
|
mov %fp, %sp
|
|
|
|
tret %o7 /* Done */
|
|
|
|
/*************************************************************************
|
|
* GDB stubs
|
|
************************************************************************/
|
|
.text
|
|
.global _brkpt_hw_int, _brkpt_sw_int
|
|
.align 4
|
|
|
|
_brkpt_hw_int:
|
|
movi %l1, 9
|
|
pfx 3
|
|
wrctl %l1
|
|
pfx 4
|
|
wrctl %l1
|
|
|
|
_brkpt_sw_int:
|
|
movi %l1, 9
|
|
pfx 3
|
|
wrctl %l1
|
|
pfx 4
|
|
wrctl %l1
|
|
|
|
tret %o7
|