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ncr539x: fix FIFO read/writing to work as expected. (nw)

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R. Belmont 2014-05-27 02:45:11 +00:00
parent 223633eca3
commit 265feab6fd
2 changed files with 11 additions and 7 deletions
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16
src/emu/machine/ncr539x.c
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@ -57,9 +57,9 @@ static const char *rdregs[16] = {
"Command", // 3 "Command", // 3
"Status", // 4 "Status", // 4
"Interrupt Status", // 5 "Interrupt Status", // 5
"Internal State", "Internal State", // 6
"Current FIFO/Internal State", "Current FIFO/Internal State", // 7
"Control Register 1", "Control Register 1", // 8
"0x9", "0x9",
"0xA", "0xA",
"Control Register 2", "Control Register 2",
@ -143,6 +143,7 @@ void ncr539x_device::device_start()
void ncr539x_device::device_reset() void ncr539x_device::device_reset()
{ {
m_fifo_ptr = 0; m_fifo_ptr = 0;
m_fifo_read_ptr = 0;
m_irq_status = 0; m_irq_status = 0;
m_status = SCSI_PHASE_STATUS; m_status = SCSI_PHASE_STATUS;
m_internal_state = 0; m_internal_state = 0;
@ -318,14 +319,15 @@ READ8_MEMBER( ncr539x_device::read )
} }
else else
{ {
rv = m_fifo[m_fifo_ptr++]; rv = m_fifo[m_fifo_read_ptr++];
m_fifo_read_ptr &= (m_fifo_size-1);
fifo_bytes--; fifo_bytes--;
m_xfer_count--; m_xfer_count--;
update_fifo_internal_state(fifo_bytes); update_fifo_internal_state(fifo_bytes);
#if VERBOSE #if VERBOSE
printf("Read %02x from FIFO[%d], FIFO now contains %d bytes (PC=%x, m_buffer_remaining %x)\n", rv, m_fifo_ptr-1, fifo_bytes, space.device().safe_pc(), m_buffer_remaining); printf("Read %02x from FIFO[%d], FIFO now contains %d bytes (PC=%x, m_buffer_remaining %x)\n", rv, m_fifo_read_ptr-1, fifo_bytes, space.device().safe_pc(), m_buffer_remaining);
#endif #endif
if (fifo_bytes == 0) if (fifo_bytes == 0)
@ -432,7 +434,8 @@ READ8_MEMBER( ncr539x_device::read )
WRITE8_MEMBER( ncr539x_device::write ) WRITE8_MEMBER( ncr539x_device::write )
{ {
#if VERBOSE #if VERBOSE
if (offset != 2) printf("539x: Write %02x @ %s (%02x) (PC=%x)\n", data, wrregs[offset], offset, space.device().safe_pc()); //if (offset != 2)
printf("539x: Write %02x @ %s (%02x) (PC=%x)\n", data, wrregs[offset], offset, space.device().safe_pc());
#endif #endif
switch (offset) switch (offset)
@ -757,6 +760,7 @@ void ncr539x_device::fifo_write(UINT8 data)
printf("539x: Write %02x @ FIFO[%x]\n", data, m_fifo_ptr); printf("539x: Write %02x @ FIFO[%x]\n", data, m_fifo_ptr);
#endif #endif
m_fifo[m_fifo_ptr++] = data; m_fifo[m_fifo_ptr++] = data;
update_fifo_internal_state(m_fifo_ptr);
if (m_selected) if (m_selected)
{ {

2
src/emu/machine/ncr539x.h
View File

@ -65,7 +65,7 @@ private:
bool m_chipid_available, m_chipid_lock; bool m_chipid_available, m_chipid_lock;
static const int m_fifo_size = 16; static const int m_fifo_size = 16;
UINT8 m_fifo_ptr, m_fifo[m_fifo_size]; UINT8 m_fifo_ptr, m_fifo_read_ptr, m_fifo[m_fifo_size];
//int m_xfer_remaining; // amount in the FIFO when we're in data in phase //int m_xfer_remaining; // amount in the FIFO when we're in data in phase