diff options
Diffstat (limited to 'src/mess/drivers/pc9801.c')
-rw-r--r-- | src/mess/drivers/pc9801.c | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/src/mess/drivers/pc9801.c b/src/mess/drivers/pc9801.c index ed1707554d1..e394c2ffbf1 100644 --- a/src/mess/drivers/pc9801.c +++ b/src/mess/drivers/pc9801.c @@ -1337,8 +1337,8 @@ inline UINT16 pc9801_state::egc_do_partial_op(int plane, UINT16 src, UINT16 pat, if(m_egc.regs[6] & 0x1000) { - src_off = 16 - (m_egc.regs[6] & 0xf); - dst_off = 16 - ((m_egc.regs[6] >> 4) & 0xf); + src_off = 15 - (m_egc.regs[6] & 0xf); + dst_off = 15 - ((m_egc.regs[6] >> 4) & 0xf); } else { @@ -1350,13 +1350,13 @@ inline UINT16 pc9801_state::egc_do_partial_op(int plane, UINT16 src, UINT16 pat, { src = src_tmp << (dst_off - src_off); src |= m_egc.leftover[plane]; - m_egc.leftover[plane] = src_tmp >> (16 - (dst_off - src_off)); + m_egc.leftover[plane] = src_tmp >> (15 - (dst_off - src_off)); } else { src = src_tmp >> (src_off - dst_off); - src |= m_egc.leftover[plane] >> dst_off; - m_egc.leftover[plane] = src_tmp << (16 - (src_off - dst_off)); + src |= m_egc.leftover[plane]; + m_egc.leftover[plane] = src_tmp << (15 - (src_off - dst_off)); } for(int i = 7; i >= 0; i--) @@ -1377,15 +1377,18 @@ void pc9801_state::egc_blit_w(UINT32 offset, UINT16 data, UINT16 mem_mask) int dst_off = (m_egc.regs[6] >> 4) & 0xf; offset &= 0x3fff; - // mask off the bits past the end of the blit - if(m_egc.count < 16) - mask &= dir ? ((1 << (m_egc.count + 1)) - 1) : ~((1 << (15 - m_egc.count)) - 1); - - // mask off the bits before the start - if(m_egc.first) + if((((m_egc.regs[2] >> 11) & 3) == 1) || ((((m_egc.regs[2] >> 11) & 3) == 2) && !BIT(m_egc.regs[2], 10))) { - m_egc.leftover[0] = m_egc.leftover[1] = m_egc.leftover[2] = m_egc.leftover[3] = 0; - mask &= dir ? ~((1 << (15 - dst_off)) - 1) : ((1 << (dst_off + 1)) - 1); + // mask off the bits past the end of the blit + if(m_egc.count < 16) + mask &= dir ? ((1 << (m_egc.count + 1)) - 1) : ~((1 << (16 - m_egc.count)) - 1); + + // mask off the bits before the start + if(m_egc.first) + { + m_egc.leftover[0] = m_egc.leftover[1] = m_egc.leftover[2] = m_egc.leftover[3] = 0; + mask &= dir ? ~((1 << (16 - dst_off)) - 1) : ((1 << (dst_off + 1)) - 1); + } } for(int i = 0; i < 4; i++) |