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Diffstat (limited to 'src/mess/drivers/pc9801.c')
-rw-r--r--src/mess/drivers/pc9801.c29
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++)