.ref-BSD-1/fpterp/fp3.s

/ fp3 -- floating simulation

i.addx:
        jsr     pc,setab
        br      1f

i.subx:
        jsr     pc,setab
        neg     bsign
1:
        tst     bsign
        beq     reta
        tst     asign
        beq     retb
        mov     areg+8,r1
        sub     breg+8,r1
        blt     1f
        beq     2f
        cmp     r1,$56.
        bge     reta
        mov     $breg,r0
        br      4f
1:
        neg     r1
        cmp     r1,$56.
        bge     retb
        mov     $areg,r0
4:
        mov     r1,-(sp)
        mov     (r0)+,r1
        mov     (r0)+,r2
        mov     (r0)+,r3
        mov     (r0)+,r4
        add     (sp),(r0)
1:
        clc
        ror     r1
        ror     r2
        ror     r3
        ror     r4
        dec     (sp)
        bgt     1b
        mov     r4,-(r0)
        mov     r3,-(r0)
        mov     r2,-(r0)
        mov     r1,-(r0)
        tst     (sp)+
2:
        mov     $areg+8,r1
        mov     $breg+8,r2
        mov     $4,r0
        cmp     asign,bsign
        bne     4f
        clc
1:
        adc     -(r1)
        bcs     3f
        add     -(r2),(r1)
2:
        dec     r0
        bne     1b
        br      5f
3:
        add     -(r2),(r1)
        sec
        br      2b
        br      5f
4:
        clc
1:
        sbc     -(r1)
        bcs     3f
        sub     -(r2),(r1)
2:
        dec     r0
        bne     1b
        br      5f
3:
        sub     -(r2),(r1)
        sec
        br      2b

saret:
        mov     $areg,r1
5:
        tst     (r1)
        bge     3f
        mov     $areg+8,r1
        mov     $4,r0
        clc
1:
        adc     -(r1)
        bcs     2f
        neg     (r1)
2:
        dec     r0
        bne     1b
        neg     -(r1)
3:
        jsr     pc,norm
        br      reta

retb:
        mov     $bsign,r1
        mov     $asign,r2
        mov     $6,r0
1:
        mov     (r1)+,(r2)+
        dec     r0
        bne     1b

reta:
        mov     r5,r2
        mov     $asign,r0
        tst     (r0)
        beq     unflo
        mov     aexp,r1
        cmp     r1,$177
        bgt     ovflo
        cmp     r1,$-177
        blt     unflo
        add     $200,r1
        swab    r1
        clc
        ror     r1
        tst     (r0)+
        bge     1f
        bis     $100000,r1
1:
        bic     $!177,(r0)
        bis     (r0)+,r1
        mov     r1,(r2)+
        mov     (r0)+,(r2)+
        bit     $m.ext,fpsr
        beq     1f
        mov     (r0)+,(r2)+
        mov     (r0)+,(r2)+
1:
        rts     pc

unflo:
        clr     (r2)+
        clr     (r2)+
        bit     $m.ext,fpsr
        beq     1f
        clr     (r2)+
        clr     (r2)+
1:
        rts     pc

ovflo:
        bis     $2,fpsr                 / set v-bit (overflow)
        jmp     ret

i.mulx:
        jsr     pc,i.mul
        br      saret

i.modx:
        jsr     pc,i.mul
        jsr     pc,norm
        mov     $asign,r0
        mov     $bsign,r1
        mov     $6,r2
1:
        mov     (r0)+,(r1)+
        dec     r2
        bne     1b
        clr     r0              / count
        mov     $200,r1         / bit
        clr     r2              / reg offset
1:
        cmp     r0,aexp
        bge     2f              / in fraction
        bic     r1,areg(r2)
        br      3f
2:
        bic     r1,breg(r2)
3:
        inc     r0
        clc
        ror     r1
        bne     1b
        mov     $100000,r1
        add     $2,r2
        cmp     r2,$8
        blt     1b
        jsr     pc,norm
        jsr     pc,reta
        cmp     r5,$ac1
        beq     1f
        cmp     r5,$ac3
        beq     1f
        bit     $200,breg
        bne     2f
        clr     bsign
2:
        add     $8,r5
        jsr     pc,retb
        sub     $8,r5
1:
        rts     pc

i.divx:
        jsr     pc,setab
        tst     bsign
        beq     ovflo
        sub     bexp,aexp
        jsr     pc,xorsign
        mov     r5,-(sp)
        mov     $areg,r0
        mov     (r0),r1
        clr     (r0)+
        mov     (r0),r2
        clr     (r0)+
        mov     (r0),r3
        clr     (r0)+
        mov     (r0),r4
        clr     (r0)+
        mov     $areg,r5
        mov     $400,-(sp)
1:
        mov     $breg,r0
        cmp     (r0)+,r1
        blt     2f
        bgt     3f
        cmp     (r0)+,r2
        blo     2f
        bhi     3f
        cmp     (r0)+,r3
        blo     2f
        bhi     3f
        cmp     (r0)+,r4
        bhi     3f
2:
        mov     $breg+10,r0
        sub     -(r0),r4
        sbc     r3
        sbc     r2
        sbc     r1
        sub     -(r0),r3
        sbc     r2
        sbc     r1
        sub     -(r0),r2
        sbc     r1
        sub     -(r0),r1
        bis     (sp),(r5)
3:
        asl     r4
        rol     r3
        rol     r2
        rol     r1
        clc
        ror     (sp)
        bne     1b
        mov     $100000,(sp)
        add     $2,r5
        cmp     r5,$areg+8
        blo     1b
        tst     (sp)+
        mov     (sp)+,r5
        jmp     saret


i.mul:
        jsr     pc,setab
        add     bexp,aexp
        dec     aexp
        jsr     pc,xorsign
        mov     r5,-(sp)
        mov     $breg+4,r5
        bit     $m.ext,fpsr
        bne     3f
1:
        clr     r0
        clr     r1
        clr     r2
        clr     r3
        clr     r4
1:
        asl     r0
        bne     2f
        inc     r0
        tst     -(r5)
2:
        cmp     r0,$400
        bne     2f
        cmp     r5,$breg
        bhi     2f
        mov     $areg,r0
        mov     r1,(r0)+
        mov     r2,(r0)+
        mov     r3,(r0)+
        mov     r4,(r0)+
        mov     (sp)+,r5
        rts     pc
2:
        clc
        ror     r1
        ror     r2
        ror     r3
        ror     r4
        bit     r0,(r5)
        beq     1b
        mov     r0,-(sp)
        mov     $areg,r0
        add     (r0)+,r1
        clr     -(sp)
        add     (r0)+,r2
        adc     (sp)
        clr     -(sp)
        add     (r0)+,r3
        adc     (sp)
        add     (r0)+,r4
        adc     r3
        adc     (sp)
        add     (sp)+,r2
        adc     (sp)
        add     (sp)+,r1
        mov     (sp)+,r0
        br      1b

3:
        mov     $bins,r5
        mov     areg,r1
        mov     areg+2,r2
        mov     areg+4,r3
        mov     areg+6,r4
        mov     r1,(r5)+
        mov     r2,(r5)+
        mov     r3,(r5)+
        mov     r4,(r5)+
        clc
        asl     r4
        rol     r3
        rol     r2
        rol     r1
        mov     r1,(r5)+
        mov     r2,(r5)+
        mov     r3,(r5)+
        mov     r4,(r5)+
        mov     $areg+10,r0
        jsr     pc,addr
        mov     r1,(r5)+
        mov     r2,(r5)+
        mov     r3,(r5)+
        mov     r4,(r5)+
        clr     r1
        clr     r2
        clr     r3
        clr     r4
        mov     $breg+6,r5
        mov     $10,-(sp)
4:
        mov     (r5),r0
        ror     (r5)
        ror     (r5)
        clc
        ror     r1
        ror     r2
        ror     r3
        ror     r4
        clc
        ror     r1
        ror     r2
        ror     r3
        ror     r4
        bic     $177774,r0
        beq     1f
        ash     $3,r0
        add     $bins,r0
        jsr     pc,addr
1:
        dec     (sp)
        bne     4b
        cmp     r5,$breg+2
        beq     1f
        mov     $10,(sp)
        br      2f
1:
        mov     $4,(sp)
2:
        tst     -(r5)
        cmp     r5,$breg
        bhis    4b
        tst     (sp)+
        clc
        ror     r1
        ror     r2
        ror     r3
        ror     r4
        mov     $areg,r0
        mov     r1,(r0)+
        mov     r2,(r0)+
        mov     r3,(r0)+
        mov     r4,(r0)+
        mov     (sp)+,r5
        rts     pc
addr:
        add     -(r0),r4
        adc     r3
        adc     r2
        adc     r1
        add     -(r0),r3
        adc     r2
        adc     r1
        add     -(r0),r2
        adc     r1
        add     -(r0),r1
        rts     pc
xorsign:
        cmp     asign,bsign
        beq     1f
        mov     $-1,asign
        rts     pc
1:
        mov     $1,asign
        rts     pc