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[/] [light8080/] [trunk/] [tools/] [c80/] [c80.lib] - Blame information for rev 71

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Line No. Rev Author Line
1 65 motilito
#asm
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;
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;------------------------------------------------------------------
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;       Small-C  Run-time Librray
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;
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;       V4d     As of July 16, 1980 (gtf)
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;                  Added EXIT() function
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;------------------------------------------------------------------
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;
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;Fetch a single byte from the address in HL and sign extend into HL
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ccgchar:
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        ld a,(hl)
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ccsxt:
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        ld l,a
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        rlca
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        sbc     a
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        ld      h,a
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        ret
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;Fetch a full 16-bit integer from the address in HL
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ccgint:
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        ld a,(hl)
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        inc     hl
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        ld      h,(hl)
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        ld l,a
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        ret
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;Store a single byte from HL at the address in DE
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ccpchar:
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        ld      a,l
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        ld      (de),a
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        ret
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;Store a 16-bit integer in HL at the address in DE
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ccpint:
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        ld      a,l
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        ld      (de),a
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        inc     de
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        ld      a,h
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        ld      (de),a
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        ret
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;Inclusive "or" HL and DE into HL
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ccor:
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        ld      a,l
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        or      e
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        ld l,a
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        ld      a,h
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        or      d
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        ld      h,a
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        ret
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;Exclusive "or" HL and DE into HL
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ccxor:
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        ld      a,l
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        xor     e
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        ld l,a
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        ld      a,h
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        xor     d
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        ld      h,a
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        ret
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;"And" HL and DE into HL
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ccand:
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        ld      a,l
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        and     e
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        ld l,a
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        ld      a,h
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        and     d
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        ld      h,a
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        ret
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;Test if HL = DE and set HL = 1 if true else 0
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cceq:
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        call cccmp
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        ret z
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        dec     hl
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        ret
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;Test if DE ~= HL
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ccne:
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        call cccmp
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        ret nz
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        dec     hl
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        ret
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;Test if DE > HL (signed)
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ccgt:
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        ex de,hl
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        call cccmp
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        ret c
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        dec     hl
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        ret
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;Test if DE <= HL (signed)
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ccle:
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        call cccmp
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        ret z
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        ret c
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        dec hl
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        ret
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;Test if DE >= HL (signed)
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ccge:
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        call cccmp
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        ret nc
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        dec hl
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        ret
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;Test if DE < HL (signed)
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cclt:
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        call cccmp
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        ret c
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        dec hl
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        ret
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; Signed compare of DE and HL
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; Performs DE - HL and sets the conditions:
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;       Carry reflects sign of difference (set means DE < HL)
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;       Zero/non-zero set according to equality.
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cccmp:
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        ld      a,e
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        sub     l
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        ld      e,a
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        ld      a,d
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        sbc     h
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        ld      hl,1
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        jp      m,cccmp1
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        or      e       ;"OR" resets carry
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        ret
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cccmp1:
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        or      e
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        scf             ;set carry to signal minus
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        ret
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;Test if DE >= HL (unsigned)
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ccuge:
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        call ccucmp
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        ret nc
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        dec hl
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        ret
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;Test if DE < HL (unsigned)
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ccult:
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        call ccucmp
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        ret c
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        dec hl
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        ret
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;Test if DE > HL (unsigned)
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ccugt:
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        ex de,hl
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        call ccucmp
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        ret c
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        dec hl
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        ret
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;Test if DE <= HL (unsigned)
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ccule:
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        call ccucmp
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        ret z
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        ret c
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        dec hl
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        ret
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;Routine to perform unsigned compare
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;carry set if DE < HL
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;zero/nonzero set accordingly
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ccucmp:
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        ld      a,d
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        cp      h
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        jp      nz,$+5
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        ld      a,e
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        cp      l
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        ld      hl,1
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        ret
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;Shift DE arithmetically right by HL and return in HL
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ccasr:
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        ex      de,hl
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        ld      a,h
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        rla
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        ld      a,h
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        rra
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        ld      h,a
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        ld      a,l
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        rra
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        ld      l,a
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        dec     e
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        jp      nz,ccasr+1
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        ret
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;Shift DE arithmetically left by HL and return in HL
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ccasl:
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        ex      de,hl
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        add     hl,hl
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        dec     e
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        jp      nz,ccasl+1
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        ret
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;Subtract HL from DE and return in HL
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ccsub:
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        ld      a,e
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        sub     l
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        ld l,a
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        ld      a,d
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        sbc     h
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        ld      h,a
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        ret
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;Form the two's complement of HL
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ccneg:
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        call cccom
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        inc     hl
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        ret
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;Form the one's complement of HL
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cccom:
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        ld      a,h
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        cpl
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        ld      h,a
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        ld      a,l
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        cpl
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        ld l,a
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        ret
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;Multiply DE by HL and return in HL
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ccmult:
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        ld      b,h
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        ld      c,l
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        ld      hl,0
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ccmult1:
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        ld      a,c
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        rrca
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        jp      nc,$+4
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        add     hl,de
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        xor     a
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        ld      a,b
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        rra
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        ld      b,a
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        ld      a,c
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        rra
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        ld      c,a
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        or      b
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        ret z
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        xor     a
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        ld      a,e
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        rla
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        ld      e,a
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        ld      a,d
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        rla
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        ld      d,a
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        or      e
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        ret z
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        jp      ccmult1
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;Divide DE by HL and return quotient in HL, remainder in DE
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ccdiv:
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        ld      b,h
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        ld      c,l
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        ld      a,d
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        xor     b
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        push af
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        ld      a,d
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        or      a
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        call m,ccdeneg
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        ld      a,b
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        or      a
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        call m,ccbcneg
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        ld      a,16
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        push af
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        ex      de,hl
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        ld      de,0
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ccdiv1:
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        add hl,hl
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        call ccrdel
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        jp      z,ccdiv2
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        call cccmpbcde
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        jp      m,ccdiv2
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        ld      a,l
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        or      1
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        ld l,a
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        ld      a,e
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        sub     c
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        ld      e,a
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        ld      a,d
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        sbc     b
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        ld      d,a
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ccdiv2:
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        pop af
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        dec     a
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        jp      z,ccdiv3
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        push af
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        jp      ccdiv1
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ccdiv3:
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        pop af
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        ret     p
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        call ccdeneg
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        ex de,hl
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        call ccdeneg
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        ex de,hl
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        ret
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ccdeneg:
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        ld      a,d
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        cpl
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        ld      d,a
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        ld      a,e
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        cpl
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        ld      e,a
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        inc     de
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        ret
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ccbcneg:
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        ld      a,b
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        cpl
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        ld      b,a
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        ld      a,c
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        cpl
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        ld      c,a
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        inc     bc
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        ret
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ccrdel:
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        ld      a,e
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        rla
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        ld      e,a
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        ld      a,d
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        rla
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        ld      d,a
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        or      e
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        ret
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cccmpbcde:
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        ld      a,e
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        sub     c
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        ld      a,d
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        sbc     b
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        ret
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#endasm

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