Subversion Repositories ft816float

; ============================================================================
;        __
;   \\__/ o\    (C) 2022  Robert Finch, Waterloo
;    \  __ /    All rights reserved.
;     \/_//     robfinch<remove>@opencores.org
;       ||
;  
;
; BSD 3-Clause License
; 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, this
;    list of conditions and the following disclaimer.
;
; 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. Neither the name of the copyright holder 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 HOLDER 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.
;                                                                          
; ============================================================================
;
; Get a floating point number
;
_GetFloatGetChar:
        move.b (a0),d1
        add.l d0,a0
        rts
_GetFloatIgnBlanks:
.0001
        bsr _GetFloatGetChar
        cmpi.b #' ',d1
        beq .0001
_GetFloatBackupChar:
        sub.l d0,a0
        rts

;-------------------------------------------------------------------------------
; Get fractional part of a number, 25 digits max, into a float register.
;
; Register Usage:
;               d1 = digit from input screen
;               d4 = digit count
;               d6 = digit scaling factor
;               fp1 = digit as float number
; Returns:
;               fp0 = fraction
;-------------------------------------------------------------------------------

_GetFraction:
        link a2,#-28
        move.l _canary,24(sp)
        movem.l d1/d4/d6,(sp)
        fmove.x fp1,12(sp)
        clr.l d6                                                        ; d6 = scale factor
        fmove.w #0,fp0                          ; fract = 0.0
        moveq #24,d4
.0002
        bsr _GetFloatGetChar
        cmpi.b #'0',d1
        blo .0001
        cmpi.b #'9',d1                          ; make sure between 0 and 9
        bhi .0001
        subi.b #'0',d1
        fscale.w #1,fp0                         ; fract * 10.0
        addq #1,d6                                              ; record scaling
        fmove.b d1,fp1                          ; fp1 = digit
        fadd fp1,fp0                                    ; fract += digit
        addq.w #1,d5                                    ; increment number of digits in number
        dbra d4,.0002
.0001
        bsr _GetFloatBackupChar
        neg d6
        fscale.l d6,fp0                         ; fract /= scale
        movem.l (sp),d1/d4/d6
        fmove.x 12(sp),fp1
        cchk 24(sp)
        unlk a2
        rts

;-------------------------------------------------------------------------------
; Get exponent part of a number, 4 digits max, into a float register.
;
; Register Usage:
;               d1 = digit from input screen
;               d2 = exponent
;               d3 = temp, number times 2
;               d4 = digit counter
; Parameters:
;               fp0 = float number
; Returns:
;               fp0 = float number with exponent factored in
;-------------------------------------------------------------------------------

_GetExponent:
        link a2,#-32
        move.l _canary,28(sp)
        movem.l d1/d2/d3/d4,(sp)
        fmove.x fp2,16(sp)
        clr.l d2                                                        ; d2 = number = 0
        fmove.w #0,fp2                          ; fp2 = exp = 0.0
        moveq #1,d3                                             ; d3 = exscale = 1
        bsr _GetFloatGetChar
        cmpi.b #'-',d1
        bne .0001
        neg.l d3                                                        ; exscale = -1
.0006
        bsr _GetFloatIgnBlanks
        bra .0002
.0001
        cmpi.b #'+',d1
        beq .0006
        bsr _GetFloatBackupChar
.0002   
        moveq #3,d4                                             ; d4 = max 4 digits
.0004
        bsr _GetFloatGetChar    ; d1 = digit char
        cmpi.b #'0',d1
        blo .0003
        cmpi.b #'9',d1                          ; ensure between 0 and 9
        bhi .0003
        subi.b #'0',d1
        add.l d2,d2                                             ; number *2
        move.l d2,d3
        lsl.l #2,d2                                             ; number *8
        add.l d3,d2                                             ; number *10    
        ext.w d1
        ext.l d1
        add.l d1,d2                                             ; number + digit
        addq.w #1,d5                                    ; increment number of digits in number
        dbra d4,.0004
.0003
        bsr _GetFloatBackupChar ; backup a character
        mulu d3,d2                                              ; *1 or *-1
        ext.l d2
        fscale.l d2,fp2                         ; exp * exmul
        fmul fp2,fp0                                    ; rval *= exp
        movem.l (sp),d1/d2/d3/d4
        fmove.x 16(sp),fp2
        cchk 28(sp)
        unlk a2
        rts     

;-------------------------------------------------------------------------------
; Get an integer number, positive or negative, 25 digits max, into a float
; register.
;
; Register Usage:
;               d1 = digit from input screen
;               d2 = digit down counter
;               d3 = sign of number '+' or '-'
;               fp1 = digit
; Modifies:
;               a0,fp0
; Returns:
;               a0 = updated buffer pointer
;               fp0 = integer number
;-------------------------------------------------------------------------------

_GetInteger:
        link a2,#-28
        move.l _canary,24(sp)
        movem.l d1/d2/d3,(sp)
        fmove.x fp1,12(sp)
        fmove.w #0,fp0
        moveq #24,d2                                    ; d2 = digit count (25 max)
        bsr _GetFloatIgnBlanks
        bsr _GetFloatGetChar    ; get the sign of the number
        cmpi.b #'+',d1
        beq .0002
.0003
        cmpi.b #'-',d1
        bne .0004
        move.b #'-',d7
.0002
        bsr _GetFloatGetChar
.0004
        cmpi.b #'0',d1                          ; only characters 0 to 9 valid
        blo .0001
        cmpi.b #'9',d1
        bhi .0001
        subi.b #'0',d1
        fscale.w #1,fp0                         ; number *10
        fmove.b d1,fp1                          ; fp1 = digit
        fadd fp1,fp0
        addq.w #1,d5
        dbra d2,.0002
.0001
        bsr _GetFloatBackupChar
        movem.l (sp),d1/d2/d3
        fmove.x 12(sp),fp1
        cchk 24(sp)
        unlk a2
        rts
                
;-------------------------------------------------------------------------------
; Get a floating point number off the input screen.
;
; Parameters:
;               a0 = pointer to buffer containing string
;               d0 = stride of buffer (increment / decrement amount)
; Register Usage:
;               d1 = character from input screen
;               d5.lo = number of digits in number, d5.hi = number of characters fetched
; Returns:
;               fp0 = number
;               a0 = updated buffer pointer
;               d0 = length of number >0 if a number
;-------------------------------------------------------------------------------

_GetFloat:
        link a2,#-32
        move.l _canary,28(sp)
        movem.l d1/d5/d7/a1,(sp)
        fmove.x fp2,16(sp)
        clr.l d5
        move.b #'+',d7                          ; assume a positive number
        move.l a0,a1                                    ; a1 = copy of pointer to buffer
        bsr _GetInteger                         ; rval = integer
        fmove.x fp0,fp2
        bsr _GetFloatGetChar
        cmpi.b #'.',d1
        beq .0004
.0005
        bsr _GetFloatBackupChar
        bra .0002
.0004
        bsr _GetFraction
        fadd fp2,fp0                                    ; rval += fraction
        bsr _GetFloatGetChar
        cmpi.b #'e',d1                          ; accept either 'e' or 'E' indicating exponent
        beq .0001
        cmpi.b #'E',d1
        bne .0005
.0001
        bsr _GetExponent                        ; factor exponent into fp0
.0002
        cmpi.b #'-',d7                          ; adjust number for sign
        bne .0003
        fneg fp0
.0003
        suba.l a0,a1                                    ; compute number of characters fetched
        move.w a1,d0                                    ; move it to d0.hi
        swap d0
        move.w d5,d0                                    ; return digit/character count in d0 (non zero for a number)
        movem.l (sp),d1/d5/d7/a1
        fmove.x 16(sp),fp2
        cchk 28(sp)
        unlk a2
        rts