SPARC: Added support for SPARC LEON2 SOC Processor.
Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
diff --git a/cpu/leon2/start.S b/cpu/leon2/start.S
new file mode 100644
index 0000000..937ea1e
--- /dev/null
+++ b/cpu/leon2/start.S
@@ -0,0 +1,661 @@
+/* This is where the SPARC/LEON3 starts
+ * Copyright (C) 2007,
+ * Daniel Hellstrom, daniel@gaisler.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 <asm/asmmacro.h>
+#include <asm/winmacro.h>
+#include <asm/psr.h>
+#include <asm/stack.h>
+#include <asm/leon.h>
+#include <version.h>
+
+/* Entry for traps which jump to a programmer-specified trap handler. */
+#define TRAPR(H) \
+ wr %g0, 0xfe0, %psr; \
+ mov %g0, %tbr; \
+ ba (H); \
+ mov %g0, %wim;
+
+#define TRAP(H) \
+ mov %psr, %l0; \
+ ba (H); \
+ nop; nop;
+
+#define TRAPI(ilevel) \
+ mov ilevel, %l7; \
+ mov %psr, %l0; \
+ b _irq_entry; \
+ mov %wim, %l3
+
+/* Unexcpected trap will halt the processor by forcing it to error state */
+#undef BAD_TRAP
+#define BAD_TRAP ta 0; nop; nop; nop;
+
+/* Software trap. Treat as BAD_TRAP for the time being... */
+#define SOFT_TRAP TRAP(_hwerr)
+
+#define PSR_INIT 0x1FC0 /* Disable traps, set s and ps */
+#define WIM_INIT 2
+
+/* All traps low-level code here must end with this macro. */
+#define RESTORE_ALL b ret_trap_entry; clr %l6;
+
+#define WRITE_PAUSE nop;nop;nop
+
+WINDOWSIZE = (16 * 4)
+ARGPUSHSIZE = (6 * 4)
+ARGPUSH = (WINDOWSIZE + 4)
+MINFRAME = (WINDOWSIZE + ARGPUSHSIZE + 4)
+
+/* Number of register windows */
+#ifndef CFG_SPARC_NWINDOWS
+#error Must define number of SPARC register windows, default is 8
+#endif
+
+#define STACK_ALIGN 8
+#define SA(X) (((X)+(STACK_ALIGN-1)) & ~(STACK_ALIGN-1))
+
+ .section ".start", "ax"
+ .globl _start, start, _trap_table
+ .globl _irq_entry, nmi_trap
+ .globl _reset_reloc
+
+/* at address 0
+ * Hardware traps
+ */
+start:
+_start:
+_trap_table:
+ TRAPR(_hardreset); ! 00 reset trap
+ BAD_TRAP; ! 01 instruction_access_exception
+ BAD_TRAP; ! 02 illegal_instruction
+ BAD_TRAP; ! 03 priveleged_instruction
+ BAD_TRAP; ! 04 fp_disabled
+ TRAP(_window_overflow); ! 05 window_overflow
+ TRAP(_window_underflow); ! 06 window_underflow
+ BAD_TRAP; ! 07 Memory Address Not Aligned
+ BAD_TRAP; ! 08 Floating Point Exception
+ BAD_TRAP; ! 09 Data Miss Exception
+ BAD_TRAP; ! 0a Tagged Instruction Ovrflw
+ BAD_TRAP; ! 0b Watchpoint Detected
+ BAD_TRAP; ! 0c
+ BAD_TRAP; ! 0d
+ BAD_TRAP; ! 0e
+ BAD_TRAP; ! 0f
+ BAD_TRAP; ! 10
+ TRAPI(1); ! 11 IRQ level 1
+ TRAPI(2); ! 12 IRQ level 2
+ TRAPI(3); ! 13 IRQ level 3
+ TRAPI(4); ! 14 IRQ level 4
+ TRAPI(5); ! 15 IRQ level 5
+ TRAPI(6); ! 16 IRQ level 6
+ TRAPI(7); ! 17 IRQ level 7
+ TRAPI(8); ! 18 IRQ level 8
+ TRAPI(9); ! 19 IRQ level 9
+ TRAPI(10); ! 1a IRQ level 10
+ TRAPI(11); ! 1b IRQ level 11
+ TRAPI(12); ! 1c IRQ level 12
+ TRAPI(13); ! 1d IRQ level 13
+ TRAPI(14); ! 1e IRQ level 14
+ TRAP(_nmi_trap); ! 1f IRQ level 15 /
+ ! NMI (non maskable interrupt)
+ BAD_TRAP; ! 20 r_register_access_error
+ BAD_TRAP; ! 21 instruction access error
+ BAD_TRAP; ! 22
+ BAD_TRAP; ! 23
+ BAD_TRAP; ! 24 co-processor disabled
+ BAD_TRAP; ! 25 uniplemented FLUSH
+ BAD_TRAP; ! 26
+ BAD_TRAP; ! 27
+ BAD_TRAP; ! 28 co-processor exception
+ BAD_TRAP; ! 29 data access error
+ BAD_TRAP; ! 2a division by zero
+ BAD_TRAP; ! 2b data store error
+ BAD_TRAP; ! 2c data access MMU miss
+ BAD_TRAP; ! 2d
+ BAD_TRAP; ! 2e
+ BAD_TRAP; ! 2f
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 30-33
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 34-37
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 38-3b
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 3c-3f
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 40-43
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 44-47
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 48-4b
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 4c-4f
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 50-53
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 54-57
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 58-5b
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 5c-5f
+
+ /* implementaion dependent */
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 60-63
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 64-67
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 68-6b
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 6c-6f
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 70-73
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 74-77
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 78-7b
+ BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP; ! 7c-7f
+
+ /* Software traps, not handled */
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! 80-83
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! 84-87
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! 88-8b
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! 8c-8f
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! 90-93
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! 94-97
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! 98-9b
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! 9c-9f
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! a0-a3
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! a4-a7
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! a8-ab
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! ac-af
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! b0-b3
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! b4-b7
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! b8-bb
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! bc-bf
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! c0-c3
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! c4-c7
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! c8-cb
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! cc-cf
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! d0-d3
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! d4-d7
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! d8-db
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! dc-df
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! e0-e3
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! e4-e7
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! e8-eb
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! ec-ef
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! f0-f3
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! f4-f7
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! f8-fb
+ SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; ! fc-ff
+/*
+ * Version string
+ */
+
+ .data
+ .globl version_string
+version_string:
+ .ascii U_BOOT_VERSION
+ .ascii " (", __DATE__, " - ", __TIME__, ")"
+ .ascii CONFIG_IDENT_STRING, "\0"
+
+ .section ".text"
+ .align 4
+
+_hardreset:
+1000:
+ flush
+ nop
+ nop
+ nop
+
+ /* Init Cache */
+ set (LEON2_PREGS+LEON_REG_CACHECTRL_OFFSET), %g1
+ set 0x0081000f, %g2
+ st %g2, [%g1]
+
+ mov %g0, %y
+ clr %g1
+ clr %g2
+ clr %g3
+ clr %g4
+ clr %g5
+ clr %g6
+ clr %g7
+
+ mov %asr17, %g3
+ and %g3, 0x1f, %g3
+clear_window:
+ mov %g0, %l0
+ mov %g0, %l1
+ mov %g0, %l2
+ mov %g0, %l3
+ mov %g0, %l4
+ mov %g0, %l5
+ mov %g0, %l6
+ mov %g0, %l7
+ mov %g0, %o0
+ mov %g0, %o1
+ mov %g0, %o2
+ mov %g0, %o3
+ mov %g0, %o4
+ mov %g0, %o5
+ mov %g0, %o6
+ mov %g0, %o7
+ subcc %g3, 1, %g3
+ bge clear_window
+ save
+
+leon2_init:
+ /* LEON2 Register Base in g1 */
+ set LEON2_PREGS, %g1
+
+leon2_init_cache:
+ /* Set Cache control register */
+ set 0x1000f, %g2
+ st %g2, [%g1 + 0x14]
+
+leon2_init_clear:
+
+ /* Clear LEON2 registers */
+ st %g0, [%g1 + LEON2_ECTRL]
+ st %g0, [%g1 + LEON2_IMASK]
+ st %g0, [%g1 + LEON2_IPEND]
+ st %g0, [%g1 + LEON2_IFORCE]
+ st %g0, [%g1 + LEON2_ICLEAR]
+ st %g0, [%g1 + LEON2_IOREG]
+ st %g0, [%g1 + LEON2_IODIR]
+ st %g0, [%g1 + LEON2_IOICONF]
+ st %g0, [%g1 + LEON2_UCTRL0]
+ st %g0, [%g1 + LEON2_UCTRL1]
+
+leon2_init_ioport:
+ /* I/O port initialization */
+ set 0xaa00, %g2
+ st %g2, [%g1 + LEON2_IOREG]
+
+leon2_init_mctrl:
+
+ /* memory config register 1 */
+ set CFG_GRLIB_MEMCFG1, %g2
+ ld [%g1], %g3 !
+ and %g3, 0x300, %g3
+ or %g2, %g3, %g2
+ st %g2, [%g1 + LEON2_MCFG1]
+ set CFG_GRLIB_MEMCFG2, %g2 ! Load memory config register 2
+#if !( defined(TSIM) || !defined(BZIMAGE))
+ st %g2, [%g1 + LEON2_MCFG2] ! only for prom version, else done by "dumon -i"
+#endif
+ set CFG_GRLIB_MEMCFG3, %g2 ! Init FT register
+ st %g2, [%g1 + LEON2_ECTRL]
+ ld [%g1 + LEON2_ECTRL], %g2
+ srl %g2, 30, %g2
+ andcc %g2, 3, %g6
+ bne,a leon2_init_wim
+ mov %g0, %asr16 ! clear err_reg
+
+leon2_init_wim:
+ set WIM_INIT, %g3
+ mov %g3, %wim
+
+leon2_init_psr:
+ set 0x1000, %g3
+ mov %psr, %g2
+ wr %g2, %g3, %psr
+ nop
+ nop
+ nop
+
+leon2_init_stackp:
+ set CFG_INIT_SP_OFFSET, %fp
+ andn %fp, 0x0f, %fp
+ sub %fp, 64, %sp
+
+cpu_init_unreloc:
+ call cpu_init_f
+ nop
+
+/* un relocated start address of monitor */
+#define TEXT_START _text
+
+/* un relocated end address of monitor */
+#define DATA_END __init_end
+
+reloc:
+ set TEXT_START,%g2
+ set DATA_END,%g3
+ set CFG_RELOC_MONITOR_BASE,%g4
+reloc_loop:
+ ldd [%g2],%l0
+ ldd [%g2+8],%l2
+ std %l0,[%g4]
+ std %l2,[%g4+8]
+ inc 16,%g2
+ subcc %g3,%g2,%g0
+ bne reloc_loop
+ inc 16,%g4
+
+ clr %l0
+ clr %l1
+ clr %l2
+ clr %l3
+ clr %g2
+
+/* register g4 contain address to start
+ * This means that BSS must be directly after data and code segments
+ *
+ * g3 is length of bss = (__bss_end-__bss_start)
+ *
+ */
+
+clr_bss:
+/* clear bss area (the relocated) */
+ set __bss_start,%g2
+ set __bss_end,%g3
+ sub %g3,%g2,%g3
+ add %g3,%g4,%g3
+ clr %g1 /* std %g0 uses g0 and g1 */
+/* clearing 16byte a time ==> linker script need to align to 16 byte offset */
+clr_bss_16:
+ std %g0,[%g4]
+ std %g0,[%g4+8]
+ inc 16,%g4
+ cmp %g3,%g4
+ bne clr_bss_16
+ nop
+
+/* add offsets to GOT table */
+fixup_got:
+ set __got_start,%g4
+ set __got_end,%g3
+/*
+ * new got offset = (old GOT-PTR (read with ld) -
+ * CFG_RELOC_MONITOR_BASE(from define) ) +
+ * Destination Address (from define)
+ */
+ set CFG_RELOC_MONITOR_BASE,%g2
+ set TEXT_START, %g1
+ add %g4,%g2,%g4
+ sub %g4,%g1,%g4
+ add %g3,%g2,%g3
+ sub %g3,%g1,%g3
+ sub %g2,%g1,%g2 ! prepare register with (new base address) -
+ ! (old base address)
+got_loop:
+ ld [%g4],%l0 ! load old GOT-PTR
+ add %l0,%g2,%l0 ! increase with (new base address) -
+ ! (old base)
+ st %l0,[%g4]
+ inc 4,%g4
+ cmp %g3,%g4
+ bne got_loop
+ nop
+
+prom_relocate:
+ set __prom_start, %g2
+ set __prom_end, %g3
+ set CFG_PROM_OFFSET, %g4
+
+prom_relocate_loop:
+ ldd [%g2],%l0
+ ldd [%g2+8],%l2
+ std %l0,[%g4]
+ std %l2,[%g4+8]
+ inc 16,%g2
+ subcc %g3,%g2,%g0
+ bne prom_relocate_loop
+ inc 16,%g4
+
+/* Trap table has been moved, lets tell CPU about
+ * the new trap table address
+ */
+
+ set CFG_RELOC_MONITOR_BASE, %g2
+ wr %g0, %g2, %tbr
+
+/* call relocate*/
+ nop
+/* Call relocated init functions */
+jump:
+ set cpu_init_f2,%o1
+ set CFG_RELOC_MONITOR_BASE,%o2
+ add %o1,%o2,%o1
+ sub %o1,%g1,%o1
+ call %o1
+ clr %o0
+
+ set board_init_f,%o1
+ set CFG_RELOC_MONITOR_BASE,%o2
+ add %o1,%o2,%o1
+ sub %o1,%g1,%o1
+ call %o1
+ clr %o0
+
+dead: ta 0 ! if call returns...
+ nop
+
+/* Interrupt handler caller,
+ * reg L7: interrupt number
+ * reg L0: psr after interrupt
+ * reg L1: PC
+ * reg L2: next PC
+ * reg L3: wim
+ */
+_irq_entry:
+ SAVE_ALL
+
+ or %l0, PSR_PIL, %g2
+ wr %g2, 0x0, %psr
+ WRITE_PAUSE
+ wr %g2, PSR_ET, %psr
+ WRITE_PAUSE
+ mov %l7, %o0 ! irq level
+ set handler_irq, %o1
+ set (CFG_RELOC_MONITOR_BASE-TEXT_BASE), %o2
+ add %o1, %o2, %o1
+ call %o1
+ add %sp, SF_REGS_SZ, %o1 ! pt_regs ptr
+ or %l0, PSR_PIL, %g2 ! restore PIL after handler_irq
+ wr %g2, PSR_ET, %psr ! keep ET up
+ WRITE_PAUSE
+
+ RESTORE_ALL
+
+!Window overflow trap handler.
+ .global _window_overflow
+
+_window_overflow:
+
+ mov %wim, %l3 ! Calculate next WIM
+ mov %g1, %l7
+ srl %l3, 1, %g1
+ sll %l3, (CFG_SPARC_NWINDOWS-1) , %l4
+ or %l4, %g1, %g1
+
+ save ! Get into window to be saved.
+ mov %g1, %wim
+ nop;
+ nop;
+ nop
+ st %l0, [%sp + 0];
+ st %l1, [%sp + 4];
+ st %l2, [%sp + 8];
+ st %l3, [%sp + 12];
+ st %l4, [%sp + 16];
+ st %l5, [%sp + 20];
+ st %l6, [%sp + 24];
+ st %l7, [%sp + 28];
+ st %i0, [%sp + 32];
+ st %i1, [%sp + 36];
+ st %i2, [%sp + 40];
+ st %i3, [%sp + 44];
+ st %i4, [%sp + 48];
+ st %i5, [%sp + 52];
+ st %i6, [%sp + 56];
+ st %i7, [%sp + 60];
+ restore ! Go back to trap window.
+ mov %l7, %g1
+ jmp %l1 ! Re-execute save.
+ rett %l2
+
+/* Window underflow trap handler. */
+
+ .global _window_underflow
+
+_window_underflow:
+
+ mov %wim, %l3 ! Calculate next WIM
+ sll %l3, 1, %l4
+ srl %l3, (CFG_SPARC_NWINDOWS-1), %l5
+ or %l5, %l4, %l5
+ mov %l5, %wim
+ nop; nop; nop
+ restore ! Two restores to get into the
+ restore ! window to restore
+ ld [%sp + 0], %l0; ! Restore window from the stack
+ ld [%sp + 4], %l1;
+ ld [%sp + 8], %l2;
+ ld [%sp + 12], %l3;
+ ld [%sp + 16], %l4;
+ ld [%sp + 20], %l5;
+ ld [%sp + 24], %l6;
+ ld [%sp + 28], %l7;
+ ld [%sp + 32], %i0;
+ ld [%sp + 36], %i1;
+ ld [%sp + 40], %i2;
+ ld [%sp + 44], %i3;
+ ld [%sp + 48], %i4;
+ ld [%sp + 52], %i5;
+ ld [%sp + 56], %i6;
+ ld [%sp + 60], %i7;
+ save ! Get back to the trap window.
+ save
+ jmp %l1 ! Re-execute restore.
+ rett %l2
+
+ retl
+
+_nmi_trap:
+ nop
+ jmp %l1
+ rett %l2
+
+_hwerr:
+ ta 0
+ nop
+ nop
+ b _hwerr ! loop infinite
+ nop
+
+/* Registers to not touch at all. */
+#define t_psr l0 /* Set by caller */
+#define t_pc l1 /* Set by caller */
+#define t_npc l2 /* Set by caller */
+#define t_wim l3 /* Set by caller */
+#define t_twinmask l4 /* Set at beginning of this entry routine. */
+#define t_kstack l5 /* Set right before pt_regs frame is built */
+#define t_retpc l6 /* If you change this, change winmacro.h header file */
+#define t_systable l7 /* Never touch this, could be the syscall table ptr. */
+#define curptr g6 /* Set after pt_regs frame is built */
+
+trap_setup:
+/* build a pt_regs trap frame. */
+ sub %fp, (SF_REGS_SZ + PT_REGS_SZ), %t_kstack
+ PT_STORE_ALL(t_kstack, t_psr, t_pc, t_npc, g2)
+
+ /* See if we are in the trap window. */
+ mov 1, %t_twinmask
+ sll %t_twinmask, %t_psr, %t_twinmask ! t_twinmask = (1 << psr)
+ andcc %t_twinmask, %t_wim, %g0
+ beq 1f ! in trap window, clean up
+ nop
+
+ /*-------------------------------------------------
+ * Spill , adjust %wim and go.
+ */
+ srl %t_wim, 0x1, %g2 ! begin computation of new %wim
+
+ set (CFG_SPARC_NWINDOWS-1), %g3 !NWINDOWS-1
+
+ sll %t_wim, %g3, %t_wim ! NWINDOWS-1
+ or %t_wim, %g2, %g2
+ and %g2, 0xff, %g2
+
+ save %g0, %g0, %g0 ! get in window to be saved
+
+ /* Set new %wim value */
+ wr %g2, 0x0, %wim
+
+ /* Save the kernel window onto the corresponding stack. */
+ RW_STORE(sp)
+
+ restore %g0, %g0, %g0
+ /*-------------------------------------------------*/
+
+1:
+ /* Trap from kernel with a window available.
+ * Just do it...
+ */
+ jmpl %t_retpc + 0x8, %g0 ! return to caller
+ mov %t_kstack, %sp ! jump onto new stack
+
+#define twin_tmp1 l4
+#define glob_tmp g4
+#define curptr g6
+ret_trap_entry:
+ wr %t_psr, 0x0, %psr ! enable nesting again, clear ET
+
+ /* Will the rett land us in the invalid window? */
+ mov 2, %g1
+ sll %g1, %t_psr, %g1
+
+ set CFG_SPARC_NWINDOWS, %g2 !NWINDOWS
+
+ srl %g1, %g2, %g2
+ or %g1, %g2, %g1
+ rd %wim, %g2
+ andcc %g2, %g1, %g0
+ be 1f ! Nope, just return from the trap
+ sll %g2, 0x1, %g1
+
+ /* We have to grab a window before returning. */
+ set (CFG_SPARC_NWINDOWS-1), %g3 !NWINDOWS-1
+
+ srl %g2, %g3, %g2
+ or %g1, %g2, %g1
+ and %g1, 0xff, %g1
+
+ wr %g1, 0x0, %wim
+
+ /* Grrr, make sure we load from the right %sp... */
+ PT_LOAD_ALL(sp, t_psr, t_pc, t_npc, g1)
+
+ restore %g0, %g0, %g0
+ RW_LOAD(sp)
+ b 2f
+ save %g0, %g0, %g0
+
+ /* Reload the entire frame in case this is from a
+ * kernel system call or whatever...
+ */
+1:
+ PT_LOAD_ALL(sp, t_psr, t_pc, t_npc, g1)
+2:
+ wr %t_psr, 0x0, %psr
+ nop;
+ nop;
+ nop
+
+ jmp %t_pc
+ rett %t_npc
+
+/* This is called from relocated C-code.
+ * It resets the system by jumping to _start
+ */
+_reset_reloc:
+ set start, %l0
+ call %l0
+ nop