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fpsup.asm
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;File: fpsup.asm
; ========================================================================
; PIC Floating point library
; ========================================================================
; Copyright (C) 1991,1997,1998,1999,2000,2001,2002,2003 Mike Gore
; All rights reserved.
;
; Redistribution and use in source and binary forms, with or without
; modification, are permitted provided that the following conditions are met:
;
; * Redistributions of source code must retain the above copyright notice,
; this list of conditions and the following disclaimer.
; * 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.
; * Neither the name of the <ORGANIZATION> nor the names of its contributors
; may be used to endorse or promote products derived from this software
; without specific prior written permission.
;
; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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
;
; Contact Information
; Mike Gore
; Infowrite Consulting
; 405 Midwood Cres.
; Waterloo Ont
; N2L 5N4
; Phone: 519-884-4943 home
; Fax: 519-885-0548 fax
; Email: [email protected] - or - [email protected]
; ========================================================================
; ========================================================================
; ***** Please Use TABS = 4 when viewing this file ****
; ========================================================================
#ifndef FPSUP_ASM
#define FPSUP_ASM
; Note: n = BITS_TR keeps all bits
_FP_KEEP_MSB: ; Keep the N MSB bits of argument, W = n
movwf ML_tmp
LOAD8I ML_cnt,BITS_TR
SUB8 ML_cnt,ML_tmp ; ML_cnt = BITS_TR - n
JMP_LE _FP_KEEP_MSB_X
MOV8 ML_tmp,ML_cnt
_FP_KEEP_MSB_LOOP1
AC32_SH_LSB
DJNZ8 ML_cnt,_FP_KEEP_MSB_LOOP1
_FP_KEEP_MSB_LOOP2
AC32_SH_MSB
DJNZ8 ML_tmp,_FP_KEEP_MSB_LOOP2
_FP_KEEP_MSB_X
ENDSUB
; Note: n = BITS_TR resets all bits
_FP_RESET_MSB: ; Reset the N MSB bits of argument , W = n
movwf ML_tmp
MOV8 ML_cnt,ML_tmp
JMP_Z _FP_RESET_MSB_X
_FP_RESET_MSB_LOOP1
AC32_SH_MSB
DJNZ8 ML_cnt,_FP_RESET_MSB_LOOP1
_FP_RESET_MSB_LOOP2
AC32_SH_LSB
DJNZ8 ML_tmp,_FP_RESET_MSB_LOOP2
_FP_RESET_MSB_X
ENDSUB
; Note: n = BITS_TR keeps all bits
_FP_KEEP_LSB: ; Keep the N LSB bits of argument, W = N
movwf ML_tmp ; ML_cnt = BITS_TR - n
LOAD8I ML_cnt,BITS_TR
SUB8 ML_cnt,ML_tmp ; W = ML_cnt
JMP _FP_RESET_MSB
;
; Note: n = BITS_TR resets all bits
;
_FP_RESET_LSB: ; Reset the N LSB bits of argument, W = N
movwf ML_tmp ; ML_cnt = BITS_TR - n
LOAD8I ML_cnt,BITS_TR
SUB8 ML_cnt,ML_tmp ; W = ML_cnt
JMP _FP_KEEP_MSB
;FP_MKINT(W)
;
; W = XEXP
; Reset all bits in AC32 < XEXP.
; Keep all bits in AC32 >= XEXP.
;
; Example [ Numbers shown at TR format 31 bit mantissa ]
; Source 1.5 = 0x7f,0, 0x60 0x00 0x00 0x00
; if XEXP = 0 then
; Result 1.0 = 0x7f,0, 0x40 0x00 0x00 0x00
; Same as FPac = (float) (int) FPc
;
_FP_MKINT: ; Reset the fraction bits in FPac less or equal to radix set by W
; MSB BITS to keep = (FPac.EXP - BIAS_TR - xexp) + 1)
movwf ML_tmp ; XEXP = W
FPac_TST
JMP_Z _FP_MKINT_X
MOV8 ML_cnt,FPac_EXP ; ML_cnt = FPac_EXP - BIAS_TR - XEXP + 1
SUB8I ML_cnt,BIAS_TR; ; Remove Bias
SUB8 ML_cnt,ML_tmp
INC8 ML_cnt
JMP_Z _FPac_CLR ; <= 0 ?
JMP_BSET ML_cnt,7,_FPac_CLR
movfw ML_cnt
JMP _FP_KEEP_MSB
_FP_MKINT_X
ENDSUB
;
; _FP_MKFRAC
; Reset all bits in AC32 > XEXP
; Keep all bits in AC32 <= XEXP
; Example [ Numbers shown at TR format 31 bit mantissa ]
; Source 1.5 = 0x7f,0, 0x60 0x00 0x00 0x00
; if XEXP = 0 then
; Result 0.5 = 0x7e,0, 0x40 0x00 0x00 0x00
;
;
; W = XEXP
_FP_MKFRAC: ; Keep the fraction bits in FPac less or equal to radix set by W
; MSB BITS to reset = (FPac.EXP - BIAS_TR - XEXP)+1
movwf ML_tmp ; XEXP = W
FPac_TST ; 0 ?
JMP_Z _FP_MKFRAC_X
MOV8 ML_cnt,FPac_EXP ; ML_cnt = FPac_EXP - BIAS_TR - XEXP + 1
SUB8I ML_cnt,BIAS_TR; ; Remove Bias
SUB8 ML_cnt,ML_tmp
INC8 ML_cnt
JMP_BSET ML_cnt,7,_FP_MKFRAC_X ; < 0 ?
movfw ML_cnt
FP_RESET_MSB
JMP _FPac_NORM
_FP_MKFRAC_X
ENDSUB
; ==================================================================
; Example SPLIT function using FP_MKFRAC and FP_MKINT
; See FP.ASM for builtin SPLIT
; FP_SPLIT()
; SPlit up Integer and fractional parts of a FLOAT
; FPac == INT, FParg == Fraction
;
; FP_SPLIT(FPac) FPac = integer part, FParg = fractional part
;_FP_SPLIT
; FPac_TST
; TRac_STORE FParg ; FParg == FPac, Save
; movlw 0
; FP_MKFRAC
; FPac_SWAP
; movlw 0
; JMP _FP_MKINT
#endif