* Patch by Scott McNutt, 04 Oct 2003:

  - add support for Altera Nios-32 CPU
  - add support for Nios Cyclone Development Kit (DK-1C20)

* Patch by Steven Scholz, 29 Sep 2003:
  - A second parameter for bootm overwrites the load address for
    "Standalone Application" images.
  - bootm sets environment variable "filesize" to the resulting
    (uncompressed) data length for "Standalone Application" images
    when autostart is set to "no". Now you can do something like
       if bootm $fpgadata $some_free_ram ; then
               fpga load 0 $some_free_ram $filesize
       fi

* Patch by Denis Peter, 25 Sept 2003:
  add support for the MIP405 Rev. C board

1 files changed, 559 insertions, 0 deletions

diff --git a/cpu/nios/traps.S b/cpu/nios/traps.S
new file mode 100644
index 00000000000..655fc635884
--- /dev/null
+++ b/cpu/nios/traps.S
@@ -0,0 +1,559 @@
+/*
+ * (C) Copyright 2003, Psyent Corporation <www.psyent.com>
+ * Scott McNutt <smcnutt@psyent.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program 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 of
+ * the License, or (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <config.h>
+
+/*************************************************************************
+ * Register window underflow
+ *
+ * The register window underflow exception occurs whenever the lowest
+ * valid register window is in use (CWP=LO_LIMIT) and a save instruction
+ * is issued. The save moves CWP below LO_LIMIT, %sp is set as normal,
+ * then the exception is generated prior to executing the instruction
+ * after the save.
+ ************************************************************************/
+	.text
+	.global _cwp_lolimit
+	.align	4
+
+_cwp_lolimit:
+
+	/* Sixteen words are always allocated by the compiler in every
+	 * procedure's stack frame, always starting at %sp, for saving
+	 * 'in' and 'local' registers on a window overflow.
+	 *
+	 * Save the 'global' and 'in' regs on stack. They are restored
+	 * at cwp = HI_LIMIT. The 'local' regs aren't in-use at this point.
+	 */
+	sts	[%sp,0], %g0		/* Save 'global' regs*/
+	sts	[%sp,1], %g1
+	sts	[%sp,2], %g2
+	sts	[%sp,3], %g3
+	sts	[%sp,4], %g4
+	sts	[%sp,5], %g5
+	sts	[%sp,6], %g6
+	sts	[%sp,7], %g7
+
+	sts	[%sp,8], %i0		/* Save 'in' regs */
+	sts	[%sp,9], %i1
+	sts	[%sp,10], %i2
+	sts	[%sp,11], %i3
+	sts	[%sp,12], %i4
+	sts	[%sp,13], %i5
+	sts	[%sp,14], %i6
+	sts	[%sp,15], %i7
+
+	/* Save current %sp and return address in a global so they are
+	 * available at cwp = HI_LIMIT ... where the 'global'/'in' regs
+	 * are restored. NOTE: %sp changes with cwp.
+	 */
+	mov	%g7, %o7
+	mov	%g6, %sp
+
+	/* Get LO_LIMIT/HI_LIMIT to know where to start & stop. Note: in
+	 * the underflow exception, cwp is __NOT__ guaranteed to be zero.
+	 * If the OCI debug module is enabled the reset value for LO_LIMIT
+	 * is 2, not 1 -- so cwp can be 1 or 0.
+	 */
+	pfx	2			/* WVALID */
+	rdctl	%g1
+	mov	%g2, %g1
+	pfx	0
+	and	%g1, 0x1f		/* g1 <- LO_LIMIT */
+	lsri	%g2, 5
+	pfx	0
+	and	%g2,0x1f		/* g2 <- HI_LIMIT */
+
+	/* Set istatus so cwp = HI_LIMIT after tret
+	 */
+	movi	%g5, 0x1f
+	lsli	%g5, 4
+	not	%g5			/* mask to clr cwp */
+	pfx	1			/* istatus */
+	rdctl	%g0
+	and	%g0, %g5		/* clear cwp field */
+
+	mov	%g4, %g2
+	lsli	%g4, 4
+	or	%g0, %g4		/* cwp = HI_LIMIT */
+	pfx	1
+	wrctl	%g0			/* update istatus */
+
+	/* Now move up the register file, saving as we go. When loop
+	 * is first entered, %g1 is at LO_LIMIT.
+	 */
+0:
+	restore				/* cwp++ */
+	sts	[%sp,0], %l0		/* Save "local" regs*/
+	sts	[%sp,1], %l1
+	sts	[%sp,2], %l2
+	sts	[%sp,3], %l3
+	sts	[%sp,4], %l4
+	sts	[%sp,5], %l5
+	sts	[%sp,6], %l6
+	sts	[%sp,7], %l7
+
+	sts	[%sp,8], %i0		/* Save 'in' regs */
+	sts	[%sp,9], %i1
+	sts	[%sp,10], %i2
+	sts	[%sp,11], %i3
+	sts	[%sp,12], %i4
+	sts	[%sp,13], %i5
+	sts	[%sp,14], %i6
+	sts	[%sp,15], %i7
+
+	cmp	%g1, %g2		/* cwp == HI_LIMIT ? */
+	skps	cc_ne			/* if so, we're done */
+	br	1f
+	nop				/* delay slot */
+
+	inc	%g1			/* g1 <- cwp++ */
+	br	0b
+	nop				/* delay slot */
+
+	/* At this point cwp = HI_LIMIT, so the global/in regs that were
+	 * in place when the underflow occurred must be restored using
+	 * the original stack pointer (saved in g6).
+	 */
+1:
+	mov	%o7, %g7		/* restore return addr */
+	mov	%sp, %g6		/* Restore original sp */
+
+	lds	%g0, [%sp,0]		/* Restore 'global' regs*/
+	lds	%g1, [%sp,1]
+	lds	%g2, [%sp,2]
+	lds	%g3, [%sp,3]
+	lds	%g4, [%sp,4]
+	lds	%g5, [%sp,5]
+	lds	%g6, [%sp,6]
+	lds	%g7, [%sp,7]
+
+	lds	%i0, [%sp,8]		/* Restore 'in' regs*/
+	lds	%i1, [%sp,9]
+	lds	%i2, [%sp,10]
+	lds	%i3, [%sp,11]
+	lds	%i4, [%sp,12]
+	lds	%i5, [%sp,13]
+	lds	%i6, [%sp,14]
+	lds	%i7, [%sp,15]
+
+	tret	%o7			/* All done */
+
+/*************************************************************************
+ * Register window overflow
+ *
+ * The register window overflow exception occurs whenever the highest
+ * valid register window is in use (cwp = HI_LIMIT) and a restore
+ * instruction is issued. Control is transferred to the overflow handler
+ * before the instruction following restore is executed.
+ *
+ * When a register window overflow exception is taken, the exception
+ * handler sees cwp at HI_LIMIT.
+ ************************************************************************/
+	.text
+	.global _cwp_hilimit
+	.align	4
+
+_cwp_hilimit:
+
+	/* Save 'global'/'in' regs on the stack -- will restore when cwp
+	 * is at LO_LIMIT. Locals don't need saving as they are going away.
+	 */
+	sts	[%sp,0], %g0		/* Save "global" regs*/
+	sts	[%sp,1], %g1
+	sts	[%sp,2], %g2
+	sts	[%sp,3], %g3
+	sts	[%sp,4], %g4
+	sts	[%sp,5], %g5
+	sts	[%sp,6], %g6
+	sts	[%sp,7], %g7
+
+	sts	[%sp,8], %i0		/* Save 'in' regs */
+	sts	[%sp,9], %i1
+	sts	[%sp,10], %i2
+	sts	[%sp,11], %i3
+	sts	[%sp,12], %i4
+	sts	[%sp,13], %i5
+	sts	[%sp,14], %i6
+	sts	[%sp,15], %i7
+
+	/* The current %sp must be available in global to restore regs
+	 * saved on stack. Need return addr as well ;-)
+	 */
+	mov	%g7, %o7
+	mov	%g6, %sp
+
+	/* Get HI_LIMIT & LO_LIMIT
+	 */
+	pfx	2			/* WVALID */
+	rdctl	%g1
+	mov	%g2, %g1
+	pfx	0
+	and	%g1, 0x1f		/* g1 <- LO_LIMIT */
+	lsri	%g2, 5
+	pfx	0
+	and	%g2,0x1f		/* g2 <- HI_LIMIT */
+
+	/* Set istatus so cwp = LO_LIMIT after tret
+	 */
+	movi	%g5, 0x1f
+	lsli	%g5, 4
+	not	%g5			/* mask to clr cwp */
+	pfx	1			/* istatus */
+	rdctl	%g0
+	and	%g0, %g5		/* clear cwp field */
+
+	mov	%g4, %g1		/* g4 <- LO_LIMIT */
+	lsli	%g4, 4
+	or	%g0, %g4		/* cwp = LO_LIMIT */
+	pfx	1
+	wrctl	%g0			/* update istatus */
+
+	/* Move to cwp = LO_LIMIT-1 and restore 'in' regs.
+	 */
+	subi	%g4,(1 << 4)		/* g4 <- LO_LIMIT - 1 */
+	rdctl	%g0
+	and	%g0, %g5		/* clear cwp field */
+	or	%g0, %g4		/* cwp = LO_LIMIT - 1 */
+	wrctl	%g0			/* update status */
+	nop
+
+	mov	%sp, %g6		/* Restore sp */
+	lds	%i0, [%sp,8]		/* Restore 'in' regs */
+	lds	%i1, [%sp,9]
+	lds	%i2, [%sp,10]
+	lds	%i3, [%sp,11]
+	lds	%i4, [%sp,12]
+	lds	%i5, [%sp,13]
+	lds	%i6, [%sp,14]		/* sp in next window */
+	lds	%i7, [%sp,15]
+
+	/* Starting at LO_LIMIT-1, move up the register file, restoring
+	 * along the way.
+	 */
+0:
+	restore				/* cwp++ */
+	lds	%l0, [%sp,0]		/* Restore 'local' regs*/
+	lds	%l1, [%sp,1]
+	lds	%l2, [%sp,2]
+	lds	%l3, [%sp,3]
+	lds	%l4, [%sp,4]
+	lds	%l5, [%sp,5]
+	lds	%l6, [%sp,6]
+	lds	%l7, [%sp,7]
+
+	lds	%i0, [%sp,8]		/* Restore 'in' regs */
+	lds	%i1, [%sp,9]
+	lds	%i2, [%sp,10]
+	lds	%i3, [%sp,11]
+	lds	%i4, [%sp,12]
+	lds	%i5, [%sp,13]
+	lds	%i6, [%sp,14]		/* sp in next window */
+	lds	%i7, [%sp,15]
+
+	cmp	%g1, %g2		/* cwp == HI_LIMIT ? */
+	skps	cc_ne			/* if so, we're done */
+	br	1f
+	nop				/* delay slot */
+
+	inc	%g1			/* cwp++ */
+	br	0b
+	nop				/* delay slot */
+
+	/* All windows have been updated at this point, but the globals
+	 * still need to be restored. Go to cwp = LO_LIMIT-1 to get
+	 * some registers to use.
+	 */
+1:
+	rdctl	%g0
+	and	%g0, %g5		/* clear cwp field */
+	or	%g0, %g4		/* cwp = LO_LIMIT - 1 */
+	wrctl	%g0			/* update status */
+	nop
+
+	/* Now there are some registers available to use in restoring
+	 * the globals.
+	 */
+	mov	%sp, %g6
+	mov	%o7, %g7
+
+	lds	%g0, [%sp,0]		/* Restore "global" regs*/
+	lds	%g1, [%sp,1]
+	lds	%g2, [%sp,2]
+	lds	%g3, [%sp,3]
+	lds	%g4, [%sp,4]
+	lds	%g5, [%sp,5]
+	lds	%g6, [%sp,6]
+	lds	%g7, [%sp,7]
+
+	/* The tret moves istatus -> status. istatus was already set for
+	 * cwp = LO_LIMIT.
+	 */
+
+	tret	%o7			/* done */
+
+/*************************************************************************
+ * Default exception handler
+ *
+ * The default handler passes control to external_interrupt(). So trap
+ * or hardware interrupt hanlders can be installed using the familiar
+ * irq_install_handler().
+ *
+ * Here, the stack is fixed-up and cwp is incremented prior to calling
+ * external_interrupt(). This lets the underflow and overflow handlers
+ * operate normally during the exception.
+ ************************************************************************/
+	.text
+	.global _def_xhandler
+	.align	4
+
+_def_xhandler:
+
+	/* Allocate some stack space: 16 words at %sp to accomodate
+	 * a reg window underflow, 8 words to save interrupted task's
+	 * 'out' regs (which are now the 'in' regs), 8 words to preserve
+	 * the 'global' regs and 3 words to save the return address,
+	 * status and istatus. istatus must be saved in the event an
+	 * underflow occurs in a dispatched handler. status is saved so
+	 * a handler can access it on stack.
+	 */
+	pfx	%hi((16+16+3) * 4)
+	subi	%fp, %lo((16+16+3) * 4)
+	mov	%sp, %fp
+
+	/* Save the 'global' regs and the interrupted task's 'out' regs
+	 * (our 'in' regs) along with the return addr, status & istatus.
+	 * First 16 words are for underflow exception.
+	 */
+	rdctl	%l0			/* status */
+	pfx	1			/* istatus */
+	rdctl	%l1
+
+	sts	[%sp,16+0], %g0		/* Save 'global' regs*/
+	sts	[%sp,16+1], %g1
+	sts	[%sp,16+2], %g2
+	sts	[%sp,16+3], %g3
+	sts	[%sp,16+4], %g4
+	sts	[%sp,16+5], %g5
+	sts	[%sp,16+6], %g6
+	sts	[%sp,16+7], %g7
+
+	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 ... this guarantees cwp is at or above LO_LIMIT.
+	 * Need to set IPRI=3 and IE=1 to enable underflow exceptions.
+	 * NOTE: only the 'out' regs have been saved ... can't touch
+	 * the 'in' or 'local' here.
+	 */
+	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
+
+	/* It's ok to call a C routine now since cwp >= LO_LIMIT,
+	 * interrupt task's registers are/will be preserved, and
+	 * underflow exceptions can be handled.
+	 */
+	pfx	%hi(external_interrupt@h)
+	movi	%o1, %lo(external_interrupt@h)
+	pfx	%xhi(external_interrupt@h)
+	movhi	%o1, %xlo(external_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 */
+
+
+/*************************************************************************
+ * Timebase Timer Interrupt -- This has identical structure to above,
+ * but calls timer_interrupt().  Doing it this way keeps things similar
+ * to other architectures (e.g. ppc).
+ ************************************************************************/
+	.text
+	.global _timebase_int
+	.align	4
+
+_timebase_int:
+
+	/* Allocate  stack space.
+	 */
+	pfx	%hi((16+16+3) * 4)
+	subi	%fp, %lo((16+16+3) * 4)
+	mov	%sp, %fp
+
+	/* Save the 'global' regs & 'out' regs (our 'in' regs)
+	 */
+	rdctl	%l0			/* status */
+	pfx	1			/* istatus */
+	rdctl	%l1
+
+	sts	[%sp,16+0], %g0		/* Save 'global' regs*/
+	sts	[%sp,16+1], %g1
+	sts	[%sp,16+2], %g2
+	sts	[%sp,16+3], %g3
+	sts	[%sp,16+4], %g4
+	sts	[%sp,16+5], %g5
+	sts	[%sp,16+6], %g6
+	sts	[%sp,16+7], %g7
+
+	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 */