Subversion Repositories NedoOS

SSG_REG = 0xfffd
SSG_DAT = 0xbffd

        macro ssg_write_reg chip_n
;e = register
;d = value
        ld bc,SSG_REG
        ld a,chip_n+%11111110
        out (c),a
        out (c),e
        ld bc,SSG_DAT
        out (c),d
        endm

ssgwritemusiconlychip0
        ld a,e
        cp 0x0e
        ret nc
ssgwrite0
;e = register
;d = value
        ssg_write_reg 0
        ret

ssgwritemusiconlychip1
        ld a,e
        cp 0x0e
        ret nc
ssgwrite1
;e = register
;d = value
        ssg_write_reg 1
        ret

ssginit
        ret

        macro ssg_write_regs
;e = base register
;d = value
;l = count
.loop
        call ssgwrite0
        call ssgwrite1
        inc e
        dec l
        jr nz,.loop
        endm

ssgmute
        ld l,3
        ld de,8
        ssg_write_regs
        ld l,14
        ld de,0
        ssg_write_regs
        ret