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Diffstat (limited to 'gpxe/src/arch/i386/prefix/unnrv2b.S')
| -rw-r--r-- | gpxe/src/arch/i386/prefix/unnrv2b.S | 184 |
1 files changed, 0 insertions, 184 deletions
diff --git a/gpxe/src/arch/i386/prefix/unnrv2b.S b/gpxe/src/arch/i386/prefix/unnrv2b.S deleted file mode 100644 index f5724c13..00000000 --- a/gpxe/src/arch/i386/prefix/unnrv2b.S +++ /dev/null @@ -1,184 +0,0 @@ -/* - * Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer - * - * This file 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. - * - * Originally this code was part of ucl the data compression library - * for upx the ``Ultimate Packer of eXecutables''. - * - * - Converted to gas assembly, and refitted to work with etherboot. - * Eric Biederman 20 Aug 2002 - * - * - Structure modified to be a subroutine call rather than an - * executable prefix. - * Michael Brown 30 Mar 2004 - * - * - Modified to be compilable as either 16-bit or 32-bit code. - * Michael Brown 9 Mar 2005 - */ - -FILE_LICENCE ( GPL2_OR_LATER ) - -/**************************************************************************** - * This file provides the decompress() and decompress16() functions - * which can be called in order to decompress an image compressed with - * the nrv2b utility in src/util. - * - * These functions are designed to be called by the prefix. They are - * position-independent code. - * - * The same basic assembly code is used to compile both - * decompress() and decompress16(). - **************************************************************************** - */ - - .text - .arch i386 - .section ".prefix.lib", "ax", @progbits - -#ifdef CODE16 -/**************************************************************************** - * decompress16 (real-mode near call, position independent) - * - * Decompress data in 16-bit mode - * - * Parameters (passed via registers): - * %ds:%esi - Start of compressed input data - * %es:%edi - Start of output buffer - * Returns: - * %ds:%esi - End of compressed input data - * %es:%edi - End of decompressed output data - * All other registers are preserved - * - * NOTE: It would be possible to build a smaller version of the - * decompression code for -DKEEP_IT_REAL by using - * #define REG(x) x - * to use 16-bit registers where possible. This would impose limits - * that the compressed data size must be in the range [1,65533-%si] - * and the uncompressed data size must be in the range [1,65536-%di] - * (where %si and %di are the input values for those registers). Note - * particularly that the lower limit is 1, not 0, and that the upper - * limit on the input (compressed) data really is 65533, since the - * algorithm may read up to three bytes beyond the end of the input - * data, since it reads dwords. - **************************************************************************** - */ - -#define REG(x) e ## x -#define ADDR32 addr32 - - .code16 - .globl decompress16 -decompress16: - -#else /* CODE16 */ - -/**************************************************************************** - * decompress (32-bit protected-mode near call, position independent) - * - * Parameters (passed via registers): - * %ds:%esi - Start of compressed input data - * %es:%edi - Start of output buffer - * Returns: - * %ds:%esi - End of compressed input data - * %es:%edi - End of decompressed output data - * All other registers are preserved - **************************************************************************** - */ - -#define REG(x) e ## x -#define ADDR32 - - .code32 - .globl decompress -decompress: - -#endif /* CODE16 */ - -#define xAX REG(ax) -#define xCX REG(cx) -#define xBP REG(bp) -#define xSI REG(si) -#define xDI REG(di) - - /* Save registers */ - push %xAX - pushl %ebx - push %xCX - push %xBP - /* Do the decompression */ - cld - xor %xBP, %xBP - dec %xBP /* last_m_off = -1 */ - jmp dcl1_n2b - -decompr_literals_n2b: - ADDR32 movsb -decompr_loop_n2b: - addl %ebx, %ebx - jnz dcl2_n2b -dcl1_n2b: - call getbit32 -dcl2_n2b: - jc decompr_literals_n2b - xor %xAX, %xAX - inc %xAX /* m_off = 1 */ -loop1_n2b: - call getbit1 - adc %xAX, %xAX /* m_off = m_off*2 + getbit() */ - call getbit1 - jnc loop1_n2b /* while(!getbit()) */ - sub $3, %xAX - jb decompr_ebpeax_n2b /* if (m_off == 2) goto decompr_ebpeax_n2b ? */ - shl $8, %xAX - ADDR32 movb (%xSI), %al /* m_off = (m_off - 3)*256 + src[ilen++] */ - inc %xSI - xor $-1, %xAX - jz decompr_end_n2b /* if (m_off == 0xffffffff) goto decomp_end_n2b */ - mov %xAX, %xBP /* last_m_off = m_off ?*/ -decompr_ebpeax_n2b: - xor %xCX, %xCX - call getbit1 - adc %xCX, %xCX /* m_len = getbit() */ - call getbit1 - adc %xCX, %xCX /* m_len = m_len*2 + getbit()) */ - jnz decompr_got_mlen_n2b /* if (m_len == 0) goto decompr_got_mlen_n2b */ - inc %xCX /* m_len++ */ -loop2_n2b: - call getbit1 - adc %xCX, %xCX /* m_len = m_len*2 + getbit() */ - call getbit1 - jnc loop2_n2b /* while(!getbit()) */ - inc %xCX - inc %xCX /* m_len += 2 */ -decompr_got_mlen_n2b: - cmp $-0xd00, %xBP - adc $1, %xCX /* m_len = m_len + 1 + (last_m_off > 0xd00) */ - push %xSI - ADDR32 lea (%xBP,%xDI), %xSI /* m_pos = dst + olen + -m_off */ - rep - es ADDR32 movsb /* dst[olen++] = *m_pos++ while(m_len > 0) */ - pop %xSI - jmp decompr_loop_n2b - - -getbit1: - addl %ebx, %ebx - jnz 1f -getbit32: - ADDR32 movl (%xSI), %ebx - sub $-4, %xSI /* sets carry flag */ - adcl %ebx, %ebx -1: - ret - -decompr_end_n2b: - /* Restore registers and return */ - pop %xBP - pop %xCX - popl %ebx - pop %xAX - ret |