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Diffstat (limited to 'util/x86emu/x86emu/decode.c')
| -rw-r--r-- | util/x86emu/x86emu/decode.c | 1149 |
1 files changed, 0 insertions, 1149 deletions
diff --git a/util/x86emu/x86emu/decode.c b/util/x86emu/x86emu/decode.c deleted file mode 100644 index 3d2ba23566..0000000000 --- a/util/x86emu/x86emu/decode.c +++ /dev/null @@ -1,1149 +0,0 @@ -/**************************************************************************** -* -* Realmode X86 Emulator Library -* -* Copyright (C) 1991-2004 SciTech Software, Inc. -* Copyright (C) David Mosberger-Tang -* Copyright (C) 1999 Egbert Eich -* -* ======================================================================== -* -* Permission to use, copy, modify, distribute, and sell this software and -* its documentation for any purpose is hereby granted without fee, -* provided that the above copyright notice appear in all copies and that -* both that copyright notice and this permission notice appear in -* supporting documentation, and that the name of the authors not be used -* in advertising or publicity pertaining to distribution of the software -* without specific, written prior permission. The authors makes no -* representations about the suitability of this software for any purpose. -* It is provided "as is" without express or implied warranty. -* -* THE AUTHORS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, -* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO -* EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR -* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF -* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR -* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR -* PERFORMANCE OF THIS SOFTWARE. -* -* ======================================================================== -* -* Language: ANSI C -* Environment: Any -* Developer: Kendall Bennett -* -* Description: This file includes subroutines which are related to -* instruction decoding and accessess of immediate data via IP. etc. -* -****************************************************************************/ - -#include "x86emui.h" - -/*----------------------------- Implementation ----------------------------*/ - -/**************************************************************************** -REMARKS: -Handles any pending asychronous interrupts. -****************************************************************************/ -static void x86emu_intr_handle(void) -{ - u8 intno; - - if (M.x86.intr & INTR_SYNCH) { - intno = M.x86.intno; - if (_X86EMU_intrTab[intno]) { - (*_X86EMU_intrTab[intno])(intno); - } else { - push_word((u16)M.x86.R_FLG); - CLEAR_FLAG(F_IF); - CLEAR_FLAG(F_TF); - push_word(M.x86.R_CS); - M.x86.R_CS = mem_access_word(intno * 4 + 2); - push_word(M.x86.R_IP); - M.x86.R_IP = mem_access_word(intno * 4); - M.x86.intr = 0; - } - } -} - -/**************************************************************************** -PARAMETERS: -intrnum - Interrupt number to raise - -REMARKS: -Raise the specified interrupt to be handled before the execution of the -next instruction. -****************************************************************************/ -void x86emu_intr_raise( - u8 intrnum) -{ - printf("%s, raising exeception %x\n", __func__, intrnum); - x86emu_dump_regs(); - M.x86.intno = intrnum; - M.x86.intr |= INTR_SYNCH; -} - -/**************************************************************************** -REMARKS: -Main execution loop for the emulator. We return from here when the system -halts, which is normally caused by a stack fault when we return from the -original real mode call. -****************************************************************************/ -void X86EMU_exec(void) -{ - u8 op1; - - M.x86.intr = 0; - DB(x86emu_end_instr();) - - for (;;) { -DB( if (CHECK_IP_FETCH()) - x86emu_check_ip_access();) - /* If debugging, save the IP and CS values. */ - SAVE_IP_CS(M.x86.R_CS, M.x86.R_IP); - INC_DECODED_INST_LEN(1); - if (M.x86.intr) { - if (M.x86.intr & INTR_HALTED) { -DB( if (M.x86.R_SP != 0) { - printf("halted\n"); - X86EMU_trace_regs(); - } - else { - if (M.x86.debug) - printf("Service completed successfully\n"); - }) - return; - } - if (((M.x86.intr & INTR_SYNCH) && (M.x86.intno == 0 || M.x86.intno == 2)) || - !ACCESS_FLAG(F_IF)) { - x86emu_intr_handle(); - } - } - op1 = (*sys_rdb)(((u32)M.x86.R_CS << 4) + (M.x86.R_IP++)); - (*x86emu_optab[op1])(op1); - //if (M.x86.debug & DEBUG_EXIT) { - // M.x86.debug &= ~DEBUG_EXIT; - // return; - //} - } -} - -/**************************************************************************** -REMARKS: -Halts the system by setting the halted system flag. -****************************************************************************/ -void X86EMU_halt_sys(void) -{ - M.x86.intr |= INTR_HALTED; -} - -/**************************************************************************** -PARAMETERS: -mod - Mod value from decoded byte -regh - Reg h value from decoded byte -regl - Reg l value from decoded byte - -REMARKS: -Raise the specified interrupt to be handled before the execution of the -next instruction. - -NOTE: Do not inline this function, as (*sys_rdb) is already inline! -****************************************************************************/ -void fetch_decode_modrm( - int *mod, - int *regh, - int *regl) -{ - int fetched; - -DB( if (CHECK_IP_FETCH()) - x86emu_check_ip_access();) - fetched = (*sys_rdb)(((u32)M.x86.R_CS << 4) + (M.x86.R_IP++)); - INC_DECODED_INST_LEN(1); - *mod = (fetched >> 6) & 0x03; - *regh = (fetched >> 3) & 0x07; - *regl = (fetched >> 0) & 0x07; -} - -/**************************************************************************** -RETURNS: -Immediate byte value read from instruction queue - -REMARKS: -This function returns the immediate byte from the instruction queue, and -moves the instruction pointer to the next value. - -NOTE: Do not inline this function, as (*sys_rdb) is already inline! -****************************************************************************/ -u8 fetch_byte_imm(void) -{ - u8 fetched; - -DB( if (CHECK_IP_FETCH()) - x86emu_check_ip_access();) - fetched = (*sys_rdb)(((u32)M.x86.R_CS << 4) + (M.x86.R_IP++)); - INC_DECODED_INST_LEN(1); - return fetched; -} - -/**************************************************************************** -RETURNS: -Immediate word value read from instruction queue - -REMARKS: -This function returns the immediate byte from the instruction queue, and -moves the instruction pointer to the next value. - -NOTE: Do not inline this function, as (*sys_rdw) is already inline! -****************************************************************************/ -u16 fetch_word_imm(void) -{ - u16 fetched; - -DB( if (CHECK_IP_FETCH()) - x86emu_check_ip_access();) - fetched = (*sys_rdw)(((u32)M.x86.R_CS << 4) + (M.x86.R_IP)); - M.x86.R_IP += 2; - INC_DECODED_INST_LEN(2); - return fetched; -} - -/**************************************************************************** -RETURNS: -Immediate lone value read from instruction queue - -REMARKS: -This function returns the immediate byte from the instruction queue, and -moves the instruction pointer to the next value. - -NOTE: Do not inline this function, as (*sys_rdw) is already inline! -****************************************************************************/ -u32 fetch_long_imm(void) -{ - u32 fetched; - -DB( if (CHECK_IP_FETCH()) - x86emu_check_ip_access();) - fetched = (*sys_rdl)(((u32)M.x86.R_CS << 4) + (M.x86.R_IP)); - M.x86.R_IP += 4; - INC_DECODED_INST_LEN(4); - return fetched; -} - -/**************************************************************************** -RETURNS: -Value of the default data segment - -REMARKS: -Inline function that returns the default data segment for the current -instruction. - -On the x86 processor, the default segment is not always DS if there is -no segment override. Address modes such as -3[BP] or 10[BP+SI] all refer to -addresses relative to SS (ie: on the stack). So, at the minimum, all -decodings of addressing modes would have to set/clear a bit describing -whether the access is relative to DS or SS. That is the function of the -cpu-state-varible M.x86.mode. There are several potential states: - - repe prefix seen (handled elsewhere) - repne prefix seen (ditto) - - cs segment override - ds segment override - es segment override - fs segment override - gs segment override - ss segment override - - ds/ss select (in absense of override) - -Each of the above 7 items are handled with a bit in the mode field. -****************************************************************************/ -_INLINE u32 get_data_segment(void) -{ -#define GET_SEGMENT(segment) - switch (M.x86.mode & SYSMODE_SEGMASK) { - case 0: /* default case: use ds register */ - case SYSMODE_SEGOVR_DS: - case SYSMODE_SEGOVR_DS | SYSMODE_SEG_DS_SS: - return M.x86.R_DS; - case SYSMODE_SEG_DS_SS: /* non-overridden, use ss register */ - return M.x86.R_SS; - case SYSMODE_SEGOVR_CS: - case SYSMODE_SEGOVR_CS | SYSMODE_SEG_DS_SS: - return M.x86.R_CS; - case SYSMODE_SEGOVR_ES: - case SYSMODE_SEGOVR_ES | SYSMODE_SEG_DS_SS: - return M.x86.R_ES; - case SYSMODE_SEGOVR_FS: - case SYSMODE_SEGOVR_FS | SYSMODE_SEG_DS_SS: - return M.x86.R_FS; - case SYSMODE_SEGOVR_GS: - case SYSMODE_SEGOVR_GS | SYSMODE_SEG_DS_SS: - return M.x86.R_GS; - case SYSMODE_SEGOVR_SS: - case SYSMODE_SEGOVR_SS | SYSMODE_SEG_DS_SS: - return M.x86.R_SS; - default: -#ifdef DEBUG - printf("error: should not happen: multiple overrides.\n"); -#endif - HALT_SYS(); - return 0; - } -} - -/**************************************************************************** -PARAMETERS: -offset - Offset to load data from - -RETURNS: -Byte value read from the absolute memory location. - -NOTE: Do not inline this function as (*sys_rdX) is already inline! -****************************************************************************/ -u8 fetch_data_byte( - uint offset) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access((u16)get_data_segment(), offset); -#endif - return (*sys_rdb)((get_data_segment() << 4) + offset); -} - -/**************************************************************************** -PARAMETERS: -offset - Offset to load data from - -RETURNS: -Word value read from the absolute memory location. - -NOTE: Do not inline this function as (*sys_rdX) is already inline! -****************************************************************************/ -u16 fetch_data_word( - uint offset) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access((u16)get_data_segment(), offset); -#endif - return (*sys_rdw)((get_data_segment() << 4) + offset); -} - -/**************************************************************************** -PARAMETERS: -offset - Offset to load data from - -RETURNS: -Long value read from the absolute memory location. - -NOTE: Do not inline this function as (*sys_rdX) is already inline! -****************************************************************************/ -u32 fetch_data_long( - uint offset) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access((u16)get_data_segment(), offset); -#endif - return (*sys_rdl)((get_data_segment() << 4) + offset); -} - -/**************************************************************************** -PARAMETERS: -segment - Segment to load data from -offset - Offset to load data from - -RETURNS: -Byte value read from the absolute memory location. - -NOTE: Do not inline this function as (*sys_rdX) is already inline! -****************************************************************************/ -u8 fetch_data_byte_abs( - uint segment, - uint offset) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access(segment, offset); -#endif - return (*sys_rdb)(((u32)segment << 4) + offset); -} - -/**************************************************************************** -PARAMETERS: -segment - Segment to load data from -offset - Offset to load data from - -RETURNS: -Word value read from the absolute memory location. - -NOTE: Do not inline this function as (*sys_rdX) is already inline! -****************************************************************************/ -u16 fetch_data_word_abs( - uint segment, - uint offset) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access(segment, offset); -#endif - return (*sys_rdw)(((u32)segment << 4) + offset); -} - -/**************************************************************************** -PARAMETERS: -segment - Segment to load data from -offset - Offset to load data from - -RETURNS: -Long value read from the absolute memory location. - -NOTE: Do not inline this function as (*sys_rdX) is already inline! -****************************************************************************/ -u32 fetch_data_long_abs( - uint segment, - uint offset) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access(segment, offset); -#endif - return (*sys_rdl)(((u32)segment << 4) + offset); -} - -/**************************************************************************** -PARAMETERS: -offset - Offset to store data at -val - Value to store - -REMARKS: -Writes a word value to an segmented memory location. The segment used is -the current 'default' segment, which may have been overridden. - -NOTE: Do not inline this function as (*sys_wrX) is already inline! -****************************************************************************/ -void store_data_byte( - uint offset, - u8 val) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access((u16)get_data_segment(), offset); -#endif - (*sys_wrb)((get_data_segment() << 4) + offset, val); -} - -/**************************************************************************** -PARAMETERS: -offset - Offset to store data at -val - Value to store - -REMARKS: -Writes a word value to an segmented memory location. The segment used is -the current 'default' segment, which may have been overridden. - -NOTE: Do not inline this function as (*sys_wrX) is already inline! -****************************************************************************/ -void store_data_word( - uint offset, - u16 val) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access((u16)get_data_segment(), offset); -#endif - (*sys_wrw)((get_data_segment() << 4) + offset, val); -} - -/**************************************************************************** -PARAMETERS: -offset - Offset to store data at -val - Value to store - -REMARKS: -Writes a long value to an segmented memory location. The segment used is -the current 'default' segment, which may have been overridden. - -NOTE: Do not inline this function as (*sys_wrX) is already inline! -****************************************************************************/ -void store_data_long( - uint offset, - u32 val) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access((u16)get_data_segment(), offset); -#endif - (*sys_wrl)((get_data_segment() << 4) + offset, val); -} - -/**************************************************************************** -PARAMETERS: -segment - Segment to store data at -offset - Offset to store data at -val - Value to store - -REMARKS: -Writes a byte value to an absolute memory location. - -NOTE: Do not inline this function as (*sys_wrX) is already inline! -****************************************************************************/ -void store_data_byte_abs( - uint segment, - uint offset, - u8 val) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access(segment, offset); -#endif - (*sys_wrb)(((u32)segment << 4) + offset, val); -} - -/**************************************************************************** -PARAMETERS: -segment - Segment to store data at -offset - Offset to store data at -val - Value to store - -REMARKS: -Writes a word value to an absolute memory location. - -NOTE: Do not inline this function as (*sys_wrX) is already inline! -****************************************************************************/ -void store_data_word_abs( - uint segment, - uint offset, - u16 val) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access(segment, offset); -#endif - (*sys_wrw)(((u32)segment << 4) + offset, val); -} - -/**************************************************************************** -PARAMETERS: -segment - Segment to store data at -offset - Offset to store data at -val - Value to store - -REMARKS: -Writes a long value to an absolute memory location. - -NOTE: Do not inline this function as (*sys_wrX) is already inline! -****************************************************************************/ -void store_data_long_abs( - uint segment, - uint offset, - u32 val) -{ -#ifdef DEBUG - if (CHECK_DATA_ACCESS()) - x86emu_check_data_access(segment, offset); -#endif - (*sys_wrl)(((u32)segment << 4) + offset, val); -} - -/**************************************************************************** -PARAMETERS: -reg - Register to decode - -RETURNS: -Pointer to the appropriate register - -REMARKS: -Return a pointer to the register given by the R/RM field of the -modrm byte, for byte operands. Also enables the decoding of instructions. -****************************************************************************/ -u8* decode_rm_byte_register( - int reg) -{ - switch (reg) { - case 0: - DECODE_PRINTF("AL"); - return &M.x86.R_AL; - case 1: - DECODE_PRINTF("CL"); - return &M.x86.R_CL; - case 2: - DECODE_PRINTF("DL"); - return &M.x86.R_DL; - case 3: - DECODE_PRINTF("BL"); - return &M.x86.R_BL; - case 4: - DECODE_PRINTF("AH"); - return &M.x86.R_AH; - case 5: - DECODE_PRINTF("CH"); - return &M.x86.R_CH; - case 6: - DECODE_PRINTF("DH"); - return &M.x86.R_DH; - case 7: - DECODE_PRINTF("BH"); - return &M.x86.R_BH; - } - HALT_SYS(); - return NULL; /* NOT REACHED OR REACHED ON ERROR */ -} - -/**************************************************************************** -PARAMETERS: -reg - Register to decode - -RETURNS: -Pointer to the appropriate register - -REMARKS: -Return a pointer to the register given by the R/RM field of the -modrm byte, for word operands. Also enables the decoding of instructions. -****************************************************************************/ -u16* decode_rm_word_register( - int reg) -{ - switch (reg) { - case 0: - DECODE_PRINTF("AX"); - return &M.x86.R_AX; - case 1: - DECODE_PRINTF("CX"); - return &M.x86.R_CX; - case 2: - DECODE_PRINTF("DX"); - return &M.x86.R_DX; - case 3: - DECODE_PRINTF("BX"); - return &M.x86.R_BX; - case 4: - DECODE_PRINTF("SP"); - return &M.x86.R_SP; - case 5: - DECODE_PRINTF("BP"); - return &M.x86.R_BP; - case 6: - DECODE_PRINTF("SI"); - return &M.x86.R_SI; - case 7: - DECODE_PRINTF("DI"); - return &M.x86.R_DI; - } - HALT_SYS(); - return NULL; /* NOTREACHED OR REACHED ON ERROR */ -} - -/**************************************************************************** -PARAMETERS: -reg - Register to decode - -RETURNS: -Pointer to the appropriate register - -REMARKS: -Return a pointer to the register given by the R/RM field of the -modrm byte, for dword operands. Also enables the decoding of instructions. -****************************************************************************/ -u32* decode_rm_long_register( - int reg) -{ - switch (reg) { - case 0: - DECODE_PRINTF("EAX"); - return &M.x86.R_EAX; - case 1: - DECODE_PRINTF("ECX"); - return &M.x86.R_ECX; - case 2: - DECODE_PRINTF("EDX"); - return &M.x86.R_EDX; - case 3: - DECODE_PRINTF("EBX"); - return &M.x86.R_EBX; - case 4: - DECODE_PRINTF("ESP"); - return &M.x86.R_ESP; - case 5: - DECODE_PRINTF("EBP"); - return &M.x86.R_EBP; - case 6: - DECODE_PRINTF("ESI"); - return &M.x86.R_ESI; - case 7: - DECODE_PRINTF("EDI"); - return &M.x86.R_EDI; - } - HALT_SYS(); - return NULL; /* NOTREACHED OR REACHED ON ERROR */ -} - -/**************************************************************************** -PARAMETERS: -reg - Register to decode - -RETURNS: -Pointer to the appropriate register - -REMARKS: -Return a pointer to the register given by the R/RM field of the -modrm byte, for word operands, modified from above for the weirdo -special case of segreg operands. Also enables the decoding of instructions. -****************************************************************************/ -u16* decode_rm_seg_register( - int reg) -{ - switch (reg) { - case 0: - DECODE_PRINTF("ES"); - return &M.x86.R_ES; - case 1: - DECODE_PRINTF("CS"); - return &M.x86.R_CS; - case 2: - DECODE_PRINTF("SS"); - return &M.x86.R_SS; - case 3: - DECODE_PRINTF("DS"); - return &M.x86.R_DS; - case 4: - DECODE_PRINTF("FS"); - return &M.x86.R_FS; - case 5: - DECODE_PRINTF("GS"); - return &M.x86.R_GS; - case 6: - case 7: - DECODE_PRINTF("ILLEGAL SEGREG"); - break; - } - HALT_SYS(); - return NULL; /* NOT REACHED OR REACHED ON ERROR */ -} - -/**************************************************************************** -PARAMETERS: -scale - scale value of SIB byte -index - index value of SIB byte - -RETURNS: -Value of scale * index - -REMARKS: -Decodes scale/index of SIB byte and returns relevant offset part of -effective address. -****************************************************************************/ -static unsigned decode_sib_si( - int scale, - int index) -{ - scale = 1 << scale; - if (scale > 1) { - DECODE_PRINTF2("[%d*", scale); - } else { - DECODE_PRINTF("["); - } - switch (index) { - case 0: - DECODE_PRINTF("EAX]"); - return M.x86.R_EAX * index; - case 1: - DECODE_PRINTF("ECX]"); - return M.x86.R_ECX * index; - case 2: - DECODE_PRINTF("EDX]"); - return M.x86.R_EDX * index; - case 3: - DECODE_PRINTF("EBX]"); - return M.x86.R_EBX * index; - case 4: - DECODE_PRINTF("0]"); - return 0; - case 5: - DECODE_PRINTF("EBP]"); - return M.x86.R_EBP * index; - case 6: - DECODE_PRINTF("ESI]"); - return M.x86.R_ESI * index; - case 7: - DECODE_PRINTF("EDI]"); - return M.x86.R_EDI * index; - } - HALT_SYS(); - return 0; /* NOT REACHED OR REACHED ON ERROR */ -} - -/**************************************************************************** -PARAMETERS: -mod - MOD value of preceding ModR/M byte - -RETURNS: -Offset in memory for the address decoding - -REMARKS: -Decodes SIB addressing byte and returns calculated effective address. -****************************************************************************/ -static unsigned decode_sib_address( - int mod) -{ - int sib = fetch_byte_imm(); - int ss = (sib >> 6) & 0x03; - int index = (sib >> 3) & 0x07; - int base = sib & 0x07; - int offset = 0; - int displacement; - - switch (base) { - case 0: - DECODE_PRINTF("[EAX]"); - offset = M.x86.R_EAX; - break; - case 1: - DECODE_PRINTF("[ECX]"); - offset = M.x86.R_ECX; - break; - case 2: - DECODE_PRINTF("[EDX]"); - offset = M.x86.R_EDX; - break; - case 3: - DECODE_PRINTF("[EBX]"); - offset = M.x86.R_EBX; - break; - case 4: - DECODE_PRINTF("[ESP]"); - offset = M.x86.R_ESP; - break; - case 5: - switch (mod) { - case 0: - displacement = (s32)fetch_long_imm(); - DECODE_PRINTF2("[%d]", displacement); - offset = displacement; - break; - case 1: - displacement = (s8)fetch_byte_imm(); - DECODE_PRINTF2("[%d][EBP]", displacement); - offset = M.x86.R_EBP + displacement; - break; - case 2: - displacement = (s32)fetch_long_imm(); - DECODE_PRINTF2("[%d][EBP]", displacement); - offset = M.x86.R_EBP + displacement; - break; - default: - HALT_SYS(); - } - DECODE_PRINTF("[EAX]"); - offset = M.x86.R_EAX; - break; - case 6: - DECODE_PRINTF("[ESI]"); - offset = M.x86.R_ESI; - break; - case 7: - DECODE_PRINTF("[EDI]"); - offset = M.x86.R_EDI; - break; - default: - HALT_SYS(); - } - offset += decode_sib_si(ss, index); - return offset; -} - -/**************************************************************************** -PARAMETERS: -rm - RM value to decode - -RETURNS: -Offset in memory for the address decoding - -REMARKS: -Return the offset given by mod=00 addressing. Also enables the -decoding of instructions. - -NOTE: The code which specifies the corresponding segment (ds vs ss) - below in the case of [BP+..]. The assumption here is that at the - point that this subroutine is called, the bit corresponding to - SYSMODE_SEG_DS_SS will be zero. After every instruction - except the segment override instructions, this bit (as well - as any bits indicating segment overrides) will be clear. So - if a SS access is needed, set this bit. Otherwise, DS access - occurs (unless any of the segment override bits are set). -****************************************************************************/ -unsigned decode_rm00_address( - int rm) -{ - unsigned offset; - - if (M.x86.mode & SYSMODE_PREFIX_ADDR) { - /* 32-bit addressing */ - switch (rm) { - case 0: - DECODE_PRINTF("[EAX]"); - return M.x86.R_EAX; - case 1: - DECODE_PRINTF("[ECX]"); - return M.x86.R_ECX; - case 2: - DECODE_PRINTF("[EDX]"); - return M.x86.R_EDX; - case 3: - DECODE_PRINTF("[EBX]"); - return M.x86.R_EBX; - case 4: - return decode_sib_address(0); - case 5: - offset = fetch_long_imm(); - DECODE_PRINTF2("[%08x]", offset); - return offset; - case 6: - DECODE_PRINTF("[ESI]"); - return M.x86.R_ESI; - case 7: - DECODE_PRINTF("[EDI]"); - return M.x86.R_EDI; - } - } else { - /* 16-bit addressing */ - switch (rm) { - case 0: - DECODE_PRINTF("[BX+SI]"); - return (M.x86.R_BX + M.x86.R_SI) & 0xffff; - case 1: - DECODE_PRINTF("[BX+DI]"); - return (M.x86.R_BX + M.x86.R_DI) & 0xffff; - case 2: - DECODE_PRINTF("[BP+SI]"); - M.x86.mode |= SYSMODE_SEG_DS_SS; - return (M.x86.R_BP + M.x86.R_SI) & 0xffff; - case 3: - DECODE_PRINTF("[BP+DI]"); - M.x86.mode |= SYSMODE_SEG_DS_SS; - return (M.x86.R_BP + M.x86.R_DI) & 0xffff; - case 4: - DECODE_PRINTF("[SI]"); - return M.x86.R_SI; - case 5: - DECODE_PRINTF("[DI]"); - return M.x86.R_DI; - case 6: - offset = fetch_word_imm(); - DECODE_PRINTF2("[%04x]", offset); - return offset; - case 7: - DECODE_PRINTF("[BX]"); - return M.x86.R_BX; - } - } - HALT_SYS(); - return 0; -} - -/**************************************************************************** -PARAMETERS: -rm - RM value to decode - -RETURNS: -Offset in memory for the address decoding - -REMARKS: -Return the offset given by mod=01 addressing. Also enables the -decoding of instructions. -****************************************************************************/ -unsigned decode_rm01_address( - int rm) -{ - int displacement; - - if (M.x86.mode & SYSMODE_PREFIX_ADDR) { - /* 32-bit addressing */ - if (rm != 4) - displacement = (s8)fetch_byte_imm(); - else - displacement = 0; - - switch (rm) { - case 0: - DECODE_PRINTF2("%d[EAX]", displacement); - return M.x86.R_EAX + displacement; - case 1: - DECODE_PRINTF2("%d[ECX]", displacement); - return M.x86.R_ECX + displacement; - case 2: - DECODE_PRINTF2("%d[EDX]", displacement); - return M.x86.R_EDX + displacement; - case 3: - DECODE_PRINTF2("%d[EBX]", displacement); - return M.x86.R_EBX + displacement; - case 4: { - int offset = decode_sib_address(1); - displacement = (s8)fetch_byte_imm(); - DECODE_PRINTF2("[%d]", displacement); - return offset + displacement; - } - case 5: - DECODE_PRINTF2("%d[EBP]", displacement); - return M.x86.R_EBP + displacement; - case 6: - DECODE_PRINTF2("%d[ESI]", displacement); - return M.x86.R_ESI + displacement; - case 7: - DECODE_PRINTF2("%d[EDI]", displacement); - return M.x86.R_EDI + displacement; - } - } else { - /* 16-bit addressing */ - displacement = (s8)fetch_byte_imm(); - switch (rm) { - case 0: - DECODE_PRINTF2("%d[BX+SI]", displacement); - return (M.x86.R_BX + M.x86.R_SI + displacement) & 0xffff; - case 1: - DECODE_PRINTF2("%d[BX+DI]", displacement); - return (M.x86.R_BX + M.x86.R_DI + displacement) & 0xffff; - case 2: - DECODE_PRINTF2("%d[BP+SI]", displacement); - M.x86.mode |= SYSMODE_SEG_DS_SS; - return (M.x86.R_BP + M.x86.R_SI + displacement) & 0xffff; - case 3: - DECODE_PRINTF2("%d[BP+DI]", displacement); - M.x86.mode |= SYSMODE_SEG_DS_SS; - return (M.x86.R_BP + M.x86.R_DI + displacement) & 0xffff; - case 4: - DECODE_PRINTF2("%d[SI]", displacement); - return (M.x86.R_SI + displacement) & 0xffff; - case 5: - DECODE_PRINTF2("%d[DI]", displacement); - return (M.x86.R_DI + displacement) & 0xffff; - case 6: - DECODE_PRINTF2("%d[BP]", displacement); - M.x86.mode |= SYSMODE_SEG_DS_SS; - return (M.x86.R_BP + displacement) & 0xffff; - case 7: - DECODE_PRINTF2("%d[BX]", displacement); - return (M.x86.R_BX + displacement) & 0xffff; - } - } - HALT_SYS(); - return 0; /* SHOULD NOT HAPPEN */ -} - -/**************************************************************************** -PARAMETERS: -rm - RM value to decode - -RETURNS: -Offset in memory for the address decoding - -REMARKS: -Return the offset given by mod=10 addressing. Also enables the -decoding of instructions. -****************************************************************************/ -unsigned decode_rm10_address( - int rm) -{ - if (M.x86.mode & SYSMODE_PREFIX_ADDR) { - int displacement; - - /* 32-bit addressing */ - if (rm != 4) - displacement = (s32)fetch_long_imm(); - else - displacement = 0; - - switch (rm) { - case 0: - DECODE_PRINTF2("%d[EAX]", displacement); - return M.x86.R_EAX + displacement; - case 1: - DECODE_PRINTF2("%d[ECX]", displacement); - return M.x86.R_ECX + displacement; - case 2: - DECODE_PRINTF2("%d[EDX]", displacement); - return M.x86.R_EDX + displacement; - case 3: - DECODE_PRINTF2("%d[EBX]", displacement); - return M.x86.R_EBX + displacement; - case 4: { - int offset = decode_sib_address(2); - displacement = (s32)fetch_long_imm(); - DECODE_PRINTF2("[%d]", displacement); - return offset + displacement; - } - case 5: - DECODE_PRINTF2("%d[EBP]", displacement); - return M.x86.R_EBP + displacement; - case 6: - DECODE_PRINTF2("%d[ESI]", displacement); - return M.x86.R_ESI + displacement; - case 7: - DECODE_PRINTF2("%d[EDI]", displacement); - return M.x86.R_EDI + displacement; - } - } else { - int displacement = (s16)fetch_word_imm(); - - /* 16-bit addressing */ - switch (rm) { - case 0: - DECODE_PRINTF2("%d[BX+SI]", displacement); - return (M.x86.R_BX + M.x86.R_SI + displacement) & 0xffff; - case 1: - DECODE_PRINTF2("%d[BX+DI]", displacement); - return (M.x86.R_BX + M.x86.R_DI + displacement) & 0xffff; - case 2: - DECODE_PRINTF2("%d[BP+SI]", displacement); - M.x86.mode |= SYSMODE_SEG_DS_SS; - return (M.x86.R_BP + M.x86.R_SI + displacement) & 0xffff; - case 3: - DECODE_PRINTF2("%d[BP+DI]", displacement); - M.x86.mode |= SYSMODE_SEG_DS_SS; - return (M.x86.R_BP + M.x86.R_DI + displacement) & 0xffff; - case 4: - DECODE_PRINTF2("%d[SI]", displacement); - return (M.x86.R_SI + displacement) & 0xffff; - case 5: - DECODE_PRINTF2("%d[DI]", displacement); - return (M.x86.R_DI + displacement) & 0xffff; - case 6: - DECODE_PRINTF2("%d[BP]", displacement); - M.x86.mode |= SYSMODE_SEG_DS_SS; - return (M.x86.R_BP + displacement) & 0xffff; - case 7: - DECODE_PRINTF2("%d[BX]", displacement); - return (M.x86.R_BX + displacement) & 0xffff; - } - } - HALT_SYS(); - return 0; /* SHOULD NOT HAPPEN */ -} - - -/**************************************************************************** -PARAMETERS: -mod - modifier -rm - RM value to decode - -RETURNS: -Offset in memory for the address decoding, multiplexing calls to -the decode_rmXX_address functions - -REMARKS: -Return the offset given by "mod" addressing. -****************************************************************************/ - -unsigned decode_rmXX_address(int mod, int rm) -{ - if(mod == 0) - return decode_rm00_address(rm); - if(mod == 1) - return decode_rm01_address(rm); - return decode_rm10_address(rm); -} - - - |