* 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
diff --git a/cpu/nios/Makefile b/cpu/nios/Makefile
new file mode 100644
index 0000000..baf752f
--- /dev/null
+++ b/cpu/nios/Makefile
@@ -0,0 +1,44 @@
+#
+# (C) Copyright 2000
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# 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 $(TOPDIR)/config.mk
+
+LIB = lib$(CPU).a
+
+START = start.o
+AOBJS = traps.o
+OBJS = cpu.o interrupts.o serial.o
+
+all: .depend $(START) $(LIB)
+
+$(LIB): $(OBJS) $(AOBJS)
+ $(AR) crv $@ $(OBJS) $(AOBJS)
+
+#########################################################################
+
+.depend: Makefile $(START:.o=.S) $(OBJS:.o=.c) $(AOBJS:.o=.S)
+ $(CC) -M $(CFLAGS) $(START:.o=.S) $(OBJS:.o=.c) $(AOBJS:.o=.S) > $@
+
+sinclude .depend
+
+#########################################################################
diff --git a/cpu/nios/config.mk b/cpu/nios/config.mk
new file mode 100644
index 0000000..9e95a0c
--- /dev/null
+++ b/cpu/nios/config.mk
@@ -0,0 +1,25 @@
+#
+# (C) Copyright 2000
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# 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
+#
+
+PLATFORM_RELFLAGS +=
+
diff --git a/cpu/nios/cpu.c b/cpu/nios/cpu.c
new file mode 100644
index 0000000..5cf1883
--- /dev/null
+++ b/cpu/nios/cpu.c
@@ -0,0 +1,78 @@
+/*
+ * (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 <common.h>
+#include <nios.h>
+
+
+int checkcpu (void)
+{
+ unsigned val;
+ unsigned rev_major;
+ unsigned rev_minor;
+ short nregs, hi_limit, lo_limit;
+
+ /* Get cpu version info */
+ val = rdctl (CTL_CPU_ID);
+ printf ("CPU: ");
+ printf ("%s", (val & 0x00008000) ? "Nios-16 " : "Nios-32 ");
+ rev_major = (val>>12) & 0x07;
+ rev_minor = val & 0x0f;
+ printf ("Rev. %d.%02d (0x%04x)", rev_major, rev_minor,
+ val & 0xffff);
+ if (rev_major == 0x08)
+ printf (" [OpenCore (R) Plus]");
+ printf ("\n");
+
+ /* Check register file */
+ val = rdctl (CTL_WVALID);
+ lo_limit = val & 0x01f;
+ hi_limit = (val>>5) & 0x1f;
+ nregs = (hi_limit + 2) * 16;
+ printf ("Reg file size: %d LO_LIMIT/HI_LIMIT: %d/%d\n",
+ nregs, lo_limit, hi_limit);
+
+ return (0);
+}
+
+
+int do_reset (void)
+{
+ /* trap 0 does the trick ... at least with the OCI debug
+ * present -- haven't tested without it yet (stm).
+ */
+ disable_interrupts ();
+ ipri (1);
+ asm volatile ("trap 0\n");
+
+ /* No return ;-) */
+
+ return(0);
+}
+
+
+#if defined(CONFIG_WATCHDOG)
+void watchdog_reset (void)
+{
+}
+#endif /* CONFIG_WATCHDOG */
diff --git a/cpu/nios/interrupts.c b/cpu/nios/interrupts.c
new file mode 100644
index 0000000..981b8f7
--- /dev/null
+++ b/cpu/nios/interrupts.c
@@ -0,0 +1,184 @@
+/*
+ * (C) Copyright 2000-2002
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * (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 <nios.h>
+#include <nios-io.h>
+#include <asm/ptrace.h>
+#include <common.h>
+#include <command.h>
+
+/****************************************************************************/
+
+struct irq_action {
+ interrupt_handler_t *handler;
+ void *arg;
+ int count;
+};
+
+static struct irq_action irq_vecs[64];
+
+/*************************************************************************/
+volatile ulong timestamp = 0;
+
+void reset_timer (void)
+{
+ timestamp = 0;
+}
+
+ulong get_timer (ulong base)
+{
+ return (timestamp - base);
+}
+
+void set_timer (ulong t)
+{
+ timestamp = t;
+}
+
+
+/* The board must handle this interrupt if a timer is not
+ * provided.
+ */
+#if defined(CFG_NIOS_TMRBASE)
+void timer_interrupt (struct pt_regs *regs)
+{
+ /* Interrupt is cleared by writing anything to the
+ * status register.
+ */
+ nios_timer_t *tmr = (nios_timer_t *)CFG_NIOS_TMRBASE;
+ tmr->status = 0;
+ timestamp += CFG_NIOS_TMRMS;
+}
+#endif
+
+/*************************************************************************/
+int disable_interrupts (void)
+{
+ int val = 0;
+
+ /* Writing anything to CLR_IE disables interrupts */
+ val = rdctl (CTL_STATUS);
+ wrctl (CTL_CLR_IE, 0);
+ return (val & STATUS_IE);
+}
+
+void enable_interrupts( void )
+{
+ /* Writing anything SET_IE enables interrupts */
+ wrctl (CTL_SET_IE, 0);
+}
+
+void external_interrupt (struct pt_regs *regs)
+{
+ unsigned vec;
+
+ vec = (regs->status & STATUS_IPRI) >> 9; /* ipri */
+
+ irq_vecs[vec].count++;
+ if (irq_vecs[vec].handler != NULL) {
+ (*irq_vecs[vec].handler)(irq_vecs[vec].arg);
+ } else {
+ /* A sad side-effect of masking a bogus interrupt is
+ * that lower priority interrupts will also be disabled.
+ * This is probably not what we want ... so hang insted.
+ */
+ printf ("Unhandled interrupt: 0x%x\n", vec);
+ disable_interrupts ();
+ hang ();
+ }
+}
+
+/*************************************************************************/
+int interrupt_init (void)
+{
+ int vec;
+
+#if defined(CFG_NIOS_TMRBASE)
+ nios_timer_t *tmr = (nios_timer_t *)CFG_NIOS_TMRBASE;
+
+ tmr->control &= ~NIOS_TIMER_ITO;
+ tmr->control |= NIOS_TIMER_STOP;
+#endif
+
+ for (vec=0; vec<64; vec++ ) {
+ irq_vecs[vec].handler = NULL;
+ irq_vecs[vec].arg = NULL;
+ irq_vecs[vec].count = 0;
+ }
+
+ /* Need timus interruptus -- start the lopri timer */
+#if defined(CFG_NIOS_TMRBASE)
+ tmr->control |= ( NIOS_TIMER_ITO |
+ NIOS_TIMER_CONT |
+ NIOS_TIMER_START );
+ ipri (CFG_NIOS_TMRIRQ + 1);
+#endif
+ enable_interrupts ();
+ return (0);
+}
+
+void irq_install_handler (int vec, interrupt_handler_t *handler, void *arg)
+{
+ struct irq_action *irqa = irq_vecs;
+ int i = vec;
+ int flag;
+
+ if (irqa[i].handler != NULL) {
+ printf ("Interrupt vector %d: handler 0x%x "
+ "replacing 0x%x\n",
+ vec, (uint)handler, (uint)irqa[i].handler);
+ }
+
+ flag = disable_interrupts ();
+ irqa[i].handler = handler;
+ irqa[i].arg = arg;
+ if (flag )
+ enable_interrupts ();
+}
+
+/*************************************************************************/
+#if (CONFIG_COMMANDS & CFG_CMD_IRQ)
+int do_irqinfo (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+ int vec;
+
+ printf ("\nInterrupt-Information:\n");
+ printf ("Nr Routine Arg CouIt's ok to cnt\n");
+
+ for (vec=0; vec<64; vec++) {
+ if (irq_vecs[vec].handler != NULL) {
+ printf ("%02d %08lx %08lx %d\n",
+ vec,
+ (ulong)irq_vecs[vec].handler<<1,
+ (ulong)irq_vecs[vec].arg,
+ irq_vecs[vec].count);
+ }
+ }
+
+ return (0);
+}
+#endif /* CONFIG_COMMANDS & CFG_CMD_IRQ */
diff --git a/cpu/nios/serial.c b/cpu/nios/serial.c
new file mode 100644
index 0000000..61b26ab
--- /dev/null
+++ b/cpu/nios/serial.c
@@ -0,0 +1,86 @@
+/*
+ * (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 <common.h>
+#include <nios-io.h>
+
+
+static nios_uart_t *uart = (nios_uart_t *)CFG_NIOS_CONSOLE;
+
+#if defined(CFG_NIOS_FIXEDBAUD)
+
+/* Everything's already setup for fixed-baud PTF
+ * assignment
+ */
+void serial_setbrg( void ){ return; }
+int serial_init( void ) { return(0);}
+
+#else
+
+void serial_setbrg( void )
+{
+ DECLARE_GLOBAL_DATA_PTR;
+ unsigned div;
+
+ div = (CONFIG_SYS_CLK_FREQ/gd->baudrate)-1;
+ uart->divisor = div;
+ return;
+}
+
+int serial_init( void )
+{
+ serial_setbrg();
+ return(0);
+}
+
+#endif /* CFG_NIOS_FIXEDBAUD */
+
+
+void serial_putc( char c )
+{
+ if (c == '\n')
+ serial_putc('\r');
+ while( (uart->status & NIOS_UART_TRDY) == 0 )
+ ;
+ uart->txdata = (unsigned char)c;
+}
+
+void serial_puts( const char *s )
+{
+ while( *s != 0 ) {
+ serial_putc( *s++ );
+ }
+}
+
+int serial_tstc( void )
+{
+ return( uart->status & NIOS_UART_RRDY);
+}
+
+int serial_getc( void )
+{
+ while( serial_tstc() == 0 )
+ ;
+ return( uart->rxdata & 0x00ff );
+}
diff --git a/cpu/nios/start.S b/cpu/nios/start.S
new file mode 100644
index 0000000..7cbd1a7
--- /dev/null
+++ b/cpu/nios/start.S
@@ -0,0 +1,186 @@
+/*
+ * (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>
+#include <version.h>
+
+#if !defined(CONFIG_IDENT_STRING)
+#define CONFIG_IDENT_STRING ""
+#endif
+
+#define STATUS_INIT 0x8600 /* IE=1, IPRI=2 */
+
+/*************************************************************************
+ * RESTART
+ ************************************************************************/
+
+ .text
+ .global _start
+
+_start:
+ bsr 0f
+ nop
+ .long _start
+
+ /* GERMS -- The "standard-32" configuration GERMS monitor looks
+ * for the string "Nios" at flash_base + 0xc (actually it only
+ * tests for 'N', 'i'). You can leave support for this in place
+ * as it's only a few words.
+ */
+ . = _start + 0x000c
+ .string "Nios"
+
+ .align 4
+0:
+ /*
+ * Early setup -- set cwp = HI_LIMIT, IPRI = 2, IE = 1 to
+ * enable underflow exceptions. Disable cache.
+ * NOTE: %o7 has return addr -- save in %g7 use later.
+ */
+ mov %g7, %o7
+
+ pfx 2 /* WVALID */
+ rdctl %g0
+ lsri %g0, 1
+ pfx %hi(STATUS_INIT)
+ or %g0, %lo(STATUS_INIT)
+ wrctl %g0 /* update status */
+ nop
+
+ /*
+ * STACK
+ */
+ pfx %hi(CFG_INIT_SP)
+ movi %sp, %lo(CFG_INIT_SP)
+ pfx %xhi(CFG_INIT_SP)
+ movhi %sp, %xlo(CFG_INIT_SP)
+ mov %fp, %sp
+
+ pfx %hi(4*16)
+ subi %sp, %lo(4*16) /* Space for reg window mgmt */
+
+ /*
+ * RELOCATE -- %g7 has return addr from bsr at _start.
+ */
+ pfx %hi(__u_boot_cmd_end)
+ movi %g5, %lo(__u_boot_cmd_end)
+ pfx %xhi(__u_boot_cmd_end)
+ movhi %g5, %xlo(__u_boot_cmd_end) /* %g5 <- end address */
+
+ lsli %g7, 1 /* mem = retaddr << 1 */
+ mov %g6, %g7
+ subi %g6, 4 /* %g6 <- src addr */
+ ld %g7, [%g7] /* %g7 <- dst addr */
+
+1: cmp %g7, %g5
+ skps cc_nz
+ br 2f
+ nop /* delay slot */
+
+ ld %g0, [%g6]
+ addi %g6, 4 /* src++ */
+ st [%g7], %g0
+ addi %g7, 4 /* dst++ */
+ br 1b
+ nop /* delay slot */
+2:
+
+ /*
+ * Jump to relocation address
+ */
+ pfx %hi(reloc@h)
+ movi %g0, %lo(reloc@h)
+ pfx %xhi(reloc@h)
+ movhi %g0, %xlo(reloc@h)
+ jmp %g0
+reloc:
+
+ /*
+ * CLEAR BSS
+ */
+ pfx %hi(__bss_end)
+ movi %g5, %lo(__bss_end)
+ pfx %xhi(__bss_end)
+ movhi %g5, %xlo(__bss_end) /* %g5 <- end address */
+ pfx %hi(__bss_start)
+ movi %g7, %lo(__bss_start)
+ pfx %xhi(__bss_start)
+ movhi %g7, %xlo(__bss_start) /* %g7 <- end address */
+
+ movi %g0, 0
+3: cmp %g7, %g5
+ skps cc_nz
+ br 4f
+ nop /* delay slot */
+
+ st [%g7], %g0
+ addi %g7, 4 /* (delay slot) dst++ */
+ br 3b
+ nop /* delay slot */
+4:
+
+ /*
+ * Call board_init -- never returns
+ */
+ pfx %hi(board_init@h)
+ movi %g1, %lo(board_init@h)
+ pfx %xhi(board_init@h)
+ movhi %g1, %xlo(board_init@h)
+ call %g1
+ nop /* Delaly slot */
+ /* NEVER RETURNS */
+
+/*
+ * dly_clks -- Nios doesn't have a time/clk reference for simple
+ * delay loops, so we do our best by counting instruction cycles.
+ * A control register that counts system clock cycles would be
+ * a handy feature -- hint for Altera ;-)
+ */
+ .globl dly_clks
+ /* Each loop is 4 instructions as delay slot is always
+ * executed. Each instruction is approximately 4 clocks
+ * (according to some lame info from Altera). So ...
+ * ... each loop is about 16 clocks.
+ */
+
+dly_clks:
+ lsri %o0, 4 /* cnt/16 */
+
+8: skprnz %o0
+ br 9f
+ subi %o0, 1 /* cnt--, Delay slot */
+ br 8b
+ nop
+
+9: lret
+ nop /* Delay slot */
+
+
+ .data
+ .globl version_string
+
+version_string:
+ .ascii U_BOOT_VERSION
+ .ascii " (", __DATE__, " - ", __TIME__, ")"
+ .ascii CONFIG_IDENT_STRING, "\0"
diff --git a/cpu/nios/traps.S b/cpu/nios/traps.S
new file mode 100644
index 0000000..655fc63
--- /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 */