--- /dev/null
+/*
+ * Copyright (C) 2011 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER )
+
+/* Initial temporary stack size */
+#define EXE_STACK_SIZE 0x400
+
+/* Temporary decompression area (avoid DOS high memory area) */
+#define EXE_DECOMPRESS_ADDRESS 0x110000
+
+/* Fields within the Program Segment Prefix */
+#define PSP_CMDLINE_LEN 0x80
+#define PSP_CMDLINE_START 0x81
+
+ .text
+ .arch i386
+ .org 0
+ .code16
+ .section ".prefix", "awx", @progbits
+
+signature:
+ /* "MZ" signature */
+ .ascii "MZ"
+
+last_block:
+ /* Number of bytes in last block that are really used */
+ .word 0
+
+blocks:
+ /* Number of 512-byte blocks */
+ .word 0
+ .section ".zinfo.fixup", "a", @progbits /* Compressor fixups */
+ .ascii "ADDW"
+ .long blocks
+ .long 512
+ .long 0
+ .previous
+
+num_reloc:
+ /* Number of relocation entries stored after the header */
+ .word 0
+
+header_pgh:
+ /* Number of paragraphs in the header */
+ .word ( ( _exe_start - signature ) / 16 )
+
+min_bss_pgh:
+ /* Minimum number of paragraphs of additional (BSS) memory */
+ .word ( EXE_STACK_SIZE / 16 )
+
+max_bss_pgh:
+ /* Maximum number of paragraphs of additional (BSS) memory */
+ .word ( EXE_STACK_SIZE / 16 )
+
+init_ss:
+ /* Initial stack segment (relative to start of executable) */
+ .word -( ( _exe_start - signature ) / 16 )
+ .section ".zinfo.fixup", "a", @progbits /* Compressor fixups */
+ .ascii "ADDW"
+ .long init_ss
+ .long 16
+ .long 0
+ .previous
+
+init_sp:
+ /* Initial stack pointer */
+ .word EXE_STACK_SIZE
+
+checksum:
+ /* Checksum (ignored) */
+ .word 0
+
+init_ip:
+ /* Initial instruction pointer */
+ .word _exe_start
+
+init_cs:
+ /* Initial code segment (relative to start of executable) */
+ .word -( ( _exe_start - signature ) / 16 )
+
+reloc_table:
+ /* Relocation table offset */
+ .word 0
+
+overlay:
+ /* Overlay number */
+ .word 0
+
+ .align 16, 0
+
+ .globl _exe_start
+_exe_start:
+ /* Install iPXE. Use a fixed temporary decompression area to
+ * avoid trashing the DOS high memory area.
+ */
+ call alloc_basemem
+ xorl %esi, %esi
+ movl $EXE_DECOMPRESS_ADDRESS, %edi
+ orl $0xffffffff, %ebp /* Allow arbitrary relocation */
+ call install_prealloc
+
+ /* Set up real-mode stack */
+ movw %bx, %ss
+ movw $_estack16, %sp
+
+ /* Jump to .text16 segment */
+ pushw %ax
+ pushw $1f
+ lret
+ .section ".text16", "awx", @progbits
+1:
+ /* Terminate command line with a NUL */
+ movzbw PSP_CMDLINE_LEN, %si
+ movb $0, PSP_CMDLINE_START(%si)
+
+ /* Calculate command line physical address */
+ xorl %esi, %esi
+ movw %ds, %si
+ shll $4, %esi
+ addl $PSP_CMDLINE_START, %esi
+
+ /* Set up %ds for access to .data16 */
+ movw %bx, %ds
+
+ /* Record command line address */
+ movl %esi, cmdline_phys
+
+ /* Run iPXE */
+ pushl $main
+ pushw %cs
+ call prot_call
+ popl %ecx /* discard */
+
+ /* Uninstall iPXE */
+ call uninstall
+
+ /* Exit back to DOS. This is very unlikely to work */
+ movw $0x4c00, %ax
+ int $0x21
Code Review / kvmfornfv.git / blobdiff