-static u8
-cirrus_get_bpp_bytes(void)
-{
- u8 v = stdvga_sequ_read(0x07) & 0x0e;
- if (v == 0x06)
- v &= 0x02;
- v >>= 1;
- if (v != 0x04)
- v++;
- return v;
-}
-
-static u16
-cirrus_get_line_offset(void)
-{
- u16 crtc_addr = stdvga_get_crtc();
- u8 reg13 = stdvga_crtc_read(crtc_addr, 0x13);
- u8 reg1b = stdvga_crtc_read(crtc_addr, 0x1b);
- return (((reg1b & 0x10) << 4) + reg13) * 8;
-}
-
-static void
-cirrus_set_start_addr(u32 addr)
-{
- u16 crtc_addr = stdvga_get_crtc();
- stdvga_crtc_write(crtc_addr, 0x0d, addr);
- stdvga_crtc_write(crtc_addr, 0x0c, addr >> 8);
- stdvga_crtc_mask(crtc_addr, 0x1d, 0x80, (addr & 0x0800) >> 4);
- stdvga_crtc_mask(crtc_addr, 0x1b, 0x0d
- , ((addr & 0x0100) >> 8) | ((addr & 0x0600) >> 7));
-}
-
-static u32
-cirrus_get_start_addr(void)
-{
- u16 crtc_addr = stdvga_get_crtc();
- u8 b2 = stdvga_crtc_read(crtc_addr, 0x0c);
- u8 b1 = stdvga_crtc_read(crtc_addr, 0x0d);
- u8 b3 = stdvga_crtc_read(crtc_addr, 0x1b);
- u8 b4 = stdvga_crtc_read(crtc_addr, 0x1d);
- return (b1 | (b2<<8) | ((b3 & 0x01) << 16) | ((b3 & 0x0c) << 15)
- | ((b4 & 0x80) << 12));
-}
-
-static void
-cirrus_vesa_07h(struct bregs *regs)
-{
- if (regs->bl == 0x80 || regs->bl == 0x00) {
- u32 addr = (cirrus_get_bpp_bytes() * regs->cx
- + cirrus_get_line_offset() * regs->dx);
- cirrus_set_start_addr(addr / 4);
- } else if (regs->bl == 0x01) {
- u32 addr = cirrus_get_start_addr() * 4;
- u32 linelength = cirrus_get_line_offset();
- regs->dx = addr / linelength;
- regs->cx = (addr % linelength) / cirrus_get_bpp_bytes();
- } else {
- regs->ax = 0x0100;
- return;
- }
-
- regs->ax = 0x004f;
-}
-