- 根目录:
- arch
- m68k
- math-emu
- fp_decode.h
/*
* fp_decode.h
*
* Copyright Roman Zippel, 1997. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, and the entire permission notice in its entirety,
* including the disclaimer of warranties.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* ALTERNATIVELY, this product may be distributed under the terms of
* the GNU General Public License, in which case the provisions of the GPL are
* required INSTEAD OF the above restrictions. (This clause is
* necessary due to a potential bad interaction between the GPL and
* the restrictions contained in a BSD-style copyright.)
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _FP_DECODE_H
#define _FP_DECODE_H
/* These macros do the dirty work of the instr decoding, several variables
* can be defined in the source file to modify the work of these macros,
* currently the following variables are used:
* ...
* The register usage:
* d0 - will contain source operand for data direct mode,
* otherwise scratch register
* d1 - upper 16bit are reserved for caller
* lower 16bit may contain further arguments,
* is destroyed during decoding
* d2 - contains first two instruction words,
* first word will be used for extension word
* a0 - will point to source/dest operand for any indirect mode
* otherwise scratch register
* a1 - scratch register
* a2 - base addr to the task structure
*
* the current implementation doesn't check for every disallowed
* addressing mode (e.g. pc relative modes as destination), as long
* as it only means a new addressing mode, which should not appear
* in a program and that doesn't crash the emulation, I think it's
* not a problem to allow these modes.
*/
do_fmovem=0
do_fmovem_cr=0
do_no_pc_mode=0
do_fscc=0
| first decoding of the instr type
| this separates the conditional instr
.macro fp_decode_cond_instr_type
bfextu %d2{#8,#2},%d0
jmp ([0f:w,%pc,%d0*4])
.align 4
0:
| .long "f<op>","fscc/fdbcc"
| .long "fbccw","fbccl"
.endm
| second decoding of the instr type
| this separates most move instr
.macro fp_decode_move_instr_type
bfextu %d2{#16,#3},%d0
jmp ([0f:w,%pc,%d0*4])
.align 4
0:
| .long "f<op> fpx,fpx","invalid instr"
| .long "f<op> <ea>,fpx","fmove fpx,<ea>"
| .long "fmovem <ea>,fpcr","fmovem <ea>,fpx"
| .long "fmovem fpcr,<ea>","fmovem fpx,<ea>"
.endm
| extract the source specifier, specifies
| either source fp register or data format
.macro fp_decode_sourcespec
bfextu %d2{#19,#3},%d0
.endm
| decode destination format for fmove reg,ea
.macro fp_decode_dest_format
bfextu %d2{#19,#3},%d0
.endm
| decode source register for fmove reg,ea
.macro fp_decode_src_reg
bfextu %d2{#22,#3},%d0
.endm
| extract the addressing mode
| it depends on the instr which of the modes is valid
.macro fp_decode_addr_mode
bfextu %d2{#10,#3},%d0
jmp ([0f:w,%pc,%d0*4])
.align 4
0:
| .long "data register direct","addr register direct"
| .long "addr register indirect"
| .long "addr register indirect postincrement"
| .long "addr register indirect predecrement"
| .long "addr register + index16"
| .long "extension mode1","extension mode2"
.endm
| extract the register for the addressing mode
.macro fp_decode_addr_reg
bfextu %d2{#13,#3},%d0
.endm
| decode the 8bit diplacement from the brief extension word
.macro fp_decode_disp8
move.b %d2,%d0
ext.w %d0
.endm
| decode the index of the brief/full extension word
.macro fp_decode_index
bfextu %d2{#17,#3},%d0 | get the register nr
btst #15,%d2 | test for data/addr register
jne 1\@f
printf PDECODE,"d%d",1,%d0
jsr fp_get_data_reg
jra 2\@f
1\@: printf PDECODE,"a%d",1,%d0
jsr fp_get_addr_reg
move.l %a0,%d0
2\@:
debug lea "'l'.w,%a0"
btst #11,%d2 | 16/32 bit size?
jne 3\@f
debug lea "'w'.w,%a0"
ext.l %d0
3\@: printf PDECODE,":%c",1,%a0
move.w %d2,%d1 | scale factor
rol.w #7,%d1
and.w #3,%d1
debug move.l "%d1,-(%sp)"
debug ext.l "%d1"
printf PDECODE,":%d",1,%d1
debug move.l "(%sp)+,%d1"
lsl.l %d1,%d0
.endm
| decode the base displacement size
.macro fp_decode_basedisp
bfextu %d2{#26,#2},%d0
jmp ([0f:w,%pc,%d0*4])
.align 4
0:
| .long "reserved","null displacement"
| .long "word displacement","long displacement"
.endm
.macro fp_decode_outerdisp
bfextu %d2{#30,#2},%d0
jmp ([0f:w,%pc,%d0*4])
.align 4
0:
| .long "no memory indirect action/reserved","null outer displacement"
| .long "word outer displacement","long outer displacement"
.endm
| get the extension word and test for brief or full extension type
.macro fp_get_test_extword label
fp_get_instr_word %d2,fp_err_ua1
btst #8,%d2
jne \label
.endm
| test if %pc is the base register for the indirect addr mode
.macro fp_test_basereg_d16 label
btst #20,%d2
jeq \label
.endm
| test if %pc is the base register for one of the extended modes
.macro fp_test_basereg_ext label
btst #19,%d2
jeq \label
.endm
.macro fp_test_suppr_index label
btst #6,%d2
jne \label
.endm
| addressing mode: data register direct
.macro fp_mode_data_direct
fp_decode_addr_reg
printf PDECODE,"d%d",1,%d0
.endm
| addressing mode: address register indirect
.macro fp_mode_addr_indirect
fp_decode_addr_reg
printf PDECODE,"(a%d)",1,%d0
jsr fp_get_addr_reg
.endm
| adjust stack for byte moves from/to stack
.macro fp_test_sp_byte_move
.if !do_fmovem
.if do_fscc
move.w #6,%d1
.endif
cmp.w #7,%d0
jne 1\@f
.if !do_fscc
cmp.w #6,%d1
jne 1\@f
.endif
move.w #4,%d1
1\@:
.endif
.endm
| addressing mode: address register indirect with postincrement
.macro fp_mode_addr_indirect_postinc
fp_decode_addr_reg
printf PDECODE,"(a%d)+",1,%d0
fp_test_sp_byte_move
jsr fp_get_addr_reg
move.l %a0,%a1 | save addr
.if do_fmovem
lea (%a0,%d1.w*4),%a0
.if !do_fmovem_cr
lea (%a0,%d1.w*8),%a0
.endif
.else
add.w (fp_datasize,%d1.w*2),%a0
.endif
jsr fp_put_addr_reg
move.l %a1,%a0
.endm
| addressing mode: address register indirect with predecrement
.macro fp_mode_addr_indirect_predec
fp_decode_addr_reg
printf PDECODE,"-(a%d)",1,%d0
fp_test_sp_byte_move
jsr fp_get_addr_reg
.if do_fmovem
.if !do_fmovem_cr
lea (-12,%a0),%a1 | setup to addr of 1st reg to move
neg.w %d1
lea (%a0,%d1.w*4),%a0
add.w %d1,%d1
lea (%a0,%d1.w*4),%a0
jsr fp_put_addr_reg
move.l %a1,%a0
.else
neg.w %d1
lea (%a0,%d1.w*4),%a0
jsr fp_put_addr_reg
.endif
.else
sub.w (fp_datasize,%d1.w*2),%a0
jsr fp_put_addr_reg
.endif
.endm
| addressing mode: address register/programm counter indirect
| with 16bit displacement
.macro fp_mode_addr_indirect_disp16
.if !do_no_pc_mode
fp_test_basereg_d16 1f
printf PDECODE,"pc"
fp_get_pc %a0
jra 2f
.endif
1: fp_decode_addr_reg
printf PDECODE,"a%d",1,%d0
jsr fp_get_addr_reg
2: fp_get_instr_word %a1,fp_err_ua1
printf PDECODE,"@(%x)",1,%a1
add.l %a1,%a0
.endm
| perform preindex (if I/IS == 0xx and xx != 00)
.macro fp_do_preindex
moveq #3,%d0
and.w %d2,%d0
jeq 1f
btst #2,%d2
jne 1f
printf PDECODE,")@("
getuser.l (%a1),%a1,fp_err_ua1,%a1
debug jra "2f"
1: printf PDECODE,","
2:
.endm
| perform postindex (if I/IS == 1xx)
.macro fp_do_postindex
btst #2,%d2
jeq 1f
printf PDECODE,")@("
getuser.l (%a1),%a1,fp_err_ua1,%a1
debug jra "2f"
1: printf PDECODE,","
2:
.endm
| all other indirect addressing modes will finally end up here
.macro fp_mode_addr_indirect_extmode0
.if !do_no_pc_mode
fp_test_basereg_ext 1f
printf PDECODE,"pc"
fp_get_pc %a0
jra 2f
.endif
1: fp_decode_addr_reg
printf PDECODE,"a%d",1,%d0
jsr fp_get_addr_reg
2: move.l %a0,%a1
swap %d2
fp_get_test_extword 3f
| addressing mode: address register/programm counter indirect
| with index and 8bit displacement
fp_decode_disp8
debug ext.l "%d0"
printf PDECODE,"@(%x,",1,%d0
add.w %d0,%a1
fp_decode_index
add.l %d0,%a1
printf PDECODE,")"
jra 9f
3: | addressing mode: address register/programm counter memory indirect
| with base and/or outer displacement
btst #7,%d2 | base register suppressed?
jeq 1f
printf PDECODE,"!"
sub.l %a1,%a1
1: printf PDECODE,"@("
fp_decode_basedisp
.long fp_ill,1f
.long 2f,3f
#ifdef FPU_EMU_DEBUG
1: printf PDECODE,"0" | null base displacement
jra 1f
#endif
2: fp_get_instr_word %a0,fp_err_ua1 | 16bit base displacement
printf PDECODE,"%x:w",1,%a0
jra 4f
3: fp_get_instr_long %a0,fp_err_ua1 | 32bit base displacement
printf PDECODE,"%x:l",1,%a0
4: add.l %a0,%a1
1:
fp_do_postindex
fp_test_suppr_index 1f
fp_decode_index
add.l %d0,%a1
1: fp_do_preindex
fp_decode_outerdisp
.long 5f,1f
.long 2f,3f
#ifdef FPU_EMU_DEBUG
1: printf PDECODE,"0" | null outer displacement
jra 1f
#endif
2: fp_get_instr_word %a0,fp_err_ua1 | 16bit outer displacement
printf PDECODE,"%x:w",1,%a0
jra 4f
3: fp_get_instr_long %a0,fp_err_ua1 | 32bit outer displacement
printf PDECODE,"%x:l",1,%a0
4: add.l %a0,%a1
1:
5: printf PDECODE,")"
9: move.l %a1,%a0
swap %d2
.endm
| get the absolute short address from user space
.macro fp_mode_abs_short
fp_get_instr_word %a0,fp_err_ua1
printf PDECODE,"%x.w",1,%a0
.endm
| get the absolute long address from user space
.macro fp_mode_abs_long
fp_get_instr_long %a0,fp_err_ua1
printf PDECODE,"%x.l",1,%a0
.endm
#endif /* _FP_DECODE_H */