Root/mips/nanonote/stage1.ccp

1#pypp 0
2// Iris: micro-kernel for a capability-based operating system.
3// mips/nanonote/sdram-setup.ccp: bootstrapping over usb.
4// Copyright 2009 Bas Wijnen <wijnen@debian.org>
5//
6// This program is free software: you can redistribute it and/or modify
7// it under the terms of the GNU General Public License as published by
8// the Free Software Foundation, either version 3 of the License, or
9// (at your option) any later version.
10//
11// This program is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15//
16// You should have received a copy of the GNU General Public License
17// along with this program. If not, see <http://www.gnu.org/licenses/>.
18
19// This runs like the kernel. In particular, it doesn't want userspace declarations.
20#define __KERNEL__
21#define dbg_log_char(x) do {} while (0)
22#define dbg_log(x) do {} while (0)
23#define dbg_log_num(...) do {} while (0)
24
25// Set up gp and sp, jump to start_cpp().
26// This must be the first code in the file,
27// so also before include jz4740.hh,
28// because that defines some static functions which may not be inlined.
29asm volatile (".set noreorder\n"
30        ".globl __start\n"
31        ".text\n"
32        "__start:\n"
33        "\tmove $t0, $ra\n" // 0
34        "\tnop\n" // 4
35        "\tbal 1f\n" // 8
36        "\tnop\n" // 12
37        "\t.word _gp\n" // 16
38        "\t.word 0\n" // 20: This is overwritten in software usbboot mode.
39        "1:\n"
40        "\tlw $gp, 0($ra)\n"
41        "\tlb $a0, 4($ra)\n"
42        "\tla $sp, stack + 0x40\n"
43        "\tla $t9, start_cpp\n"
44        "\tmove $ra, $t0\n"
45        "\tjr $t9\n"
46        "\tnop\n"
47        ".set reorder")
48
49#include "jz4740.hh"
50
51void kdebug (unsigned ch):
52    while !(UART0_LSR & UARTLSR_TDRQ):
53    UART0_TDR = ch
54    while !(UART0_LSR & UARTLSR_TEMT):
55
56extern "C":
57    void start_cpp (int skip_memsetup)
58    char stack[0x40]
59
60void start_cpp (int skip_memsetup):
61    setup_uart (true)
62    kdebug ('.')
63    if !skip_memsetup:
64        setup_sdram ()
65    kdebug ('!')
66    // everything is ok now: return to boot loader to load stage 2.
67

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