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99 lines
3.3 KiB
C
99 lines
3.3 KiB
C
/* Bra.h -- Branch converters for executables
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2023-04-02 : Igor Pavlov : Public domain */
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#ifndef ZIP7_INC_BRA_H
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#define ZIP7_INC_BRA_H
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#include "7zTypes.h"
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EXTERN_C_BEGIN
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#define Z7_BRANCH_CONV_DEC(name) z7_BranchConv_ ## name ## _Dec
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#define Z7_BRANCH_CONV_ENC(name) z7_BranchConv_ ## name ## _Enc
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#define Z7_BRANCH_CONV_ST_DEC(name) z7_BranchConvSt_ ## name ## _Dec
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#define Z7_BRANCH_CONV_ST_ENC(name) z7_BranchConvSt_ ## name ## _Enc
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#define Z7_BRANCH_CONV_DECL(name) Byte * name(Byte *data, SizeT size, UInt32 pc)
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#define Z7_BRANCH_CONV_ST_DECL(name) Byte * name(Byte *data, SizeT size, UInt32 pc, UInt32 *state)
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typedef Z7_BRANCH_CONV_DECL( (*z7_Func_BranchConv));
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typedef Z7_BRANCH_CONV_ST_DECL((*z7_Func_BranchConvSt));
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#define Z7_BRANCH_CONV_ST_X86_STATE_INIT_VAL 0
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Z7_BRANCH_CONV_ST_DECL(Z7_BRANCH_CONV_ST_DEC(X86));
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Z7_BRANCH_CONV_ST_DECL(Z7_BRANCH_CONV_ST_ENC(X86));
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#define Z7_BRANCH_FUNCS_DECL(name) \
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Z7_BRANCH_CONV_DECL(Z7_BRANCH_CONV_DEC(name)); \
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Z7_BRANCH_CONV_DECL(Z7_BRANCH_CONV_ENC(name));
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Z7_BRANCH_FUNCS_DECL(ARM64)
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Z7_BRANCH_FUNCS_DECL(ARM)
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Z7_BRANCH_FUNCS_DECL(ARMT)
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Z7_BRANCH_FUNCS_DECL(PPC)
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Z7_BRANCH_FUNCS_DECL(SPARC)
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Z7_BRANCH_FUNCS_DECL(IA64)
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/*
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These functions convert data that contain CPU instructions.
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Each such function converts relative addresses to absolute addresses in some
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branch instructions: CALL (in all converters) and JUMP (X86 converter only).
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Such conversion allows to increase compression ratio, if we compress that data.
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There are 2 types of converters:
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Byte * Conv_RISC (Byte *data, SizeT size, UInt32 pc);
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Byte * ConvSt_X86(Byte *data, SizeT size, UInt32 pc, UInt32 *state);
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Each Converter supports 2 versions: one for encoding
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and one for decoding (_Enc/_Dec postfixes in function name).
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In params:
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data : data buffer
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size : size of data
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pc : current virtual Program Counter (Instruction Pinter) value
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In/Out param:
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state : pointer to state variable (for X86 converter only)
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Return:
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The pointer to position in (data) buffer after last byte that was processed.
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If the caller calls converter again, it must call it starting with that position.
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But the caller is allowed to move data in buffer. so pointer to
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current processed position also will be changed for next call.
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Also the caller must increase internal (pc) value for next call.
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Each converter has some characteristics: Endian, Alignment, LookAhead.
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Type Endian Alignment LookAhead
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X86 little 1 4
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ARMT little 2 2
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ARM little 4 0
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ARM64 little 4 0
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PPC big 4 0
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SPARC big 4 0
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IA64 little 16 0
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(data) must be aligned for (Alignment).
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processed size can be calculated as:
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SizeT processed = Conv(data, size, pc) - data;
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if (processed == 0)
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it means that converter needs more data for processing.
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If (size < Alignment + LookAhead)
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then (processed == 0) is allowed.
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Example code for conversion in loop:
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UInt32 pc = 0;
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size = 0;
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for (;;)
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{
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size += Load_more_input_data(data + size);
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SizeT processed = Conv(data, size, pc) - data;
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if (processed == 0 && no_more_input_data_after_size)
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break; // we stop convert loop
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data += processed;
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size -= processed;
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pc += processed;
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}
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*/
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EXTERN_C_END
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#endif
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