# patch-2.2.18 linux/arch/m68k/math-emu/fp_decode.h

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• Lines: 418
• Date: Fri Oct 13 23:36:54 2000
• Orig file: v2.2.17/arch/m68k/math-emu/fp_decode.h
• Orig date: Thu Jan 1 01:00:00 1970

diff -u --new-file --recursive --exclude-from /usr/src/exclude v2.2.17/arch/m68k/math-emu/fp_decode.h linux/arch/m68k/math-emu/fp_decode.h
@@ -0,0 +1,417 @@
+/*
+ * fp_decode.h
+ *
+ *
+ * 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 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
+ *
+ * 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 seperates 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 seperates 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
+
+| it depends on the instr which of the modes is valid
+	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 postincrement"
+|	.long	"addr register indirect predecrement"
+|	.long	"addr register + index16"
+|	.long	"extension mode1","extension mode2"
+.endm
+
+| extract the register for the addressing mode
+	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
+	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
+	printf	PDECODE,"d%d",1,%d0
+.endm
+
+	printf	PDECODE,"(a%d)",1,%d0
+.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
+
+	printf	PDECODE,"(a%d)+",1,%d0
+	fp_test_sp_byte_move
+	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
+	.endif
+	move.l	%a1,%a0
+.endm
+
+	printf	PDECODE,"-(a%d)",1,%d0
+	fp_test_sp_byte_move
+	.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
+	lea	(%a0,%d1.w*4),%a0
+	move.l	%a1,%a0
+	.else
+	neg.w	%d1
+	lea	(%a0,%d1.w*4),%a0
+	.endif
+	.else
+	sub.w	(fp_datasize,%d1.w*2),%a0
+	.endif
+.endm
+
+|		   with 16bit displacement
+	.if	!do_no_pc_mode
+	fp_test_basereg_d16 1f
+	printf	PDECODE,"pc"
+	fp_get_pc %a0
+	jra	2f
+	.endif
+	printf	PDECODE,"a%d",1,%d0
+2:	fp_get_instr_word %a1,fp_err_ua1
+	printf	PDECODE,"@(%x)",1,%a1
+.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
+	.if	!do_no_pc_mode
+	fp_test_basereg_ext 1f
+	printf	PDECODE,"pc"
+	fp_get_pc %a0
+	jra	2f
+	.endif
+	printf	PDECODE,"a%d",1,%d0
+2:	move.l	%a0,%a1
+	swap	%d2
+	fp_get_test_extword 3f
+	|		   with index and 8bit displacement
+	fp_decode_disp8
+debug	ext.l	"%d0"
+	printf	PDECODE,"@(%x,",1,%d0
+	fp_decode_index
+	printf	PDECODE,")"
+	jra	9f
+	|		   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
+1:
+	fp_do_postindex
+	fp_test_suppr_index 1f
+	fp_decode_index
+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
+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 */