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jlechner |
/* SCARTS (32-bit) target-dependent code for the GNU simulator.
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Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
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Free Software Foundation, Inc.
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Contributed by Martin Walter <mwalter@opencores.org>
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This file is part of the GNU simulators.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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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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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include <string.h>
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#include "gdb/sim-scarts_32.h"
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#include "scarts_32-bootmem.h"
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static int is_reset;
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static uint16_t bootmem[SCARTS_BOOTMEM_SIZE];
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void
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scarts_bootmem_init (void)
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{
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/* The boot memory is initialized with the implementation of a minimal
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* bootloader which sets the program counter to SCARTS_CODEMEM_LMA by
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* a jmp INSN.
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*
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* Assembler code:
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* ldhi r13, (SCARTS_CODEMEM_LMA >> 24) & 0xFF
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* ldliu r13, (SCARTS_CODEMEM_LMA >> 16) & 0xFF
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* sli r13,0x8
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* ldliu r13, (SCARTS_CODEMEM_LMA >> 8) & 0xFF
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* sli r13,0x8
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* ldliu r13, SCARTS_CODEMEM_LMA & 0xFF
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* jmp r13
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*/
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bootmem[0] = (0x1 << 12) | ((SCARTS_CODEMEM_LMA >> 24) & 0xFF) << 4 | 0xD;
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bootmem[1] = (0x2 << 12) | ((SCARTS_CODEMEM_LMA >> 16) & 0xFF) << 4 | 0xD;
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bootmem[2] = 0xA18D;
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bootmem[3] = (0x2 << 12) | ((SCARTS_CODEMEM_LMA >> 8) & 0xFF) << 4 | 0xD;
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bootmem[4] = 0xA18D;
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bootmem[5] = (0x2 << 12) | (SCARTS_CODEMEM_LMA & 0xFF) << 4 | 0xD;
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bootmem[6] = 0xEF0D;
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}
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int
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scarts_bootmem_read (uint32_t addr, uint16_t* value)
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{
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if (addr >= SCARTS_BOOTMEM_SIZE)
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return 0;
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*value = bootmem[addr];
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return 1;
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}
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int
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scarts_bootmem_write (uint32_t addr, uint16_t value)
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{
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if (addr >= SCARTS_BOOTMEM_SIZE)
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return 0;
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if (is_reset == 0)
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{
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/* Make sure that the boot memory gets reset
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* before a custom program is written to it. */
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memset (bootmem, 0, sizeof (uint16_t) * SCARTS_BOOTMEM_SIZE);
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is_reset = 1;
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}
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bootmem[addr] = value;
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return 1;
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}
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