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Diffstat (limited to 'src/devices/machine/spg2xx_sysdma.cpp')
-rw-r--r--src/devices/machine/spg2xx_sysdma.cpp117
1 files changed, 117 insertions, 0 deletions
diff --git a/src/devices/machine/spg2xx_sysdma.cpp b/src/devices/machine/spg2xx_sysdma.cpp
new file mode 100644
index 00000000000..fe0d61ea395
--- /dev/null
+++ b/src/devices/machine/spg2xx_sysdma.cpp
@@ -0,0 +1,117 @@
+// license:BSD-3-Clause
+// copyright-holders:Ryan Holtz
+/*****************************************************************************
+
+ SunPlus SPG2xx-series SoC peripheral emulation (System DMA)
+
+**********************************************************************/
+
+#include "emu.h"
+#include "spg2xx_sysdma.h"
+
+DEFINE_DEVICE_TYPE(SPG2XX_SYSDMA, spg2xx_sysdma_device, "spg2xx_sysdma", "SPG240-series System-on-a-Chip System DMA")
+
+#define LOG_DMA (1U << 9)
+#define LOG_ALL (LOG_DMA)
+
+#define VERBOSE (0)
+#include "logmacro.h"
+
+
+
+spg2xx_sysdma_device::spg2xx_sysdma_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+ : device_t(mconfig, SPG2XX_SYSDMA, tag, owner, clock)
+ , m_cpu(*this, finder_base::DUMMY_TAG)
+{
+}
+
+void spg2xx_sysdma_device::device_start()
+{
+ save_item(NAME(m_dma_regs));
+}
+
+void spg2xx_sysdma_device::device_reset()
+{
+ memset(m_dma_regs, 0, 0x4 * sizeof(uint16_t));
+}
+
+/*************************
+* Machine Hardware *
+*************************/
+
+READ16_MEMBER(spg2xx_sysdma_device::dma_r)
+{
+ offset &= 0x3;
+
+ uint16_t val = m_dma_regs[offset];
+ switch (offset)
+ {
+
+ case 0x000: // DMA Source (L)
+ LOGMASKED(LOG_DMA, "dma_r: DMA Source (lo) = %04x\n", val);
+ break;
+
+ case 0x001: // DMA Source (H)
+ LOGMASKED(LOG_DMA, "dma_r: DMA Source (hi) = %04x\n", val);
+ break;
+
+ case 0x002: // DMA Length
+ LOGMASKED(LOG_DMA, "dma_r: DMA Length = %04x\n", 0);
+ val = 0;
+ break;
+
+ case 0x003: // DMA Destination
+ LOGMASKED(LOG_DMA, "dma_r: DMA Dest = %04x\n", val);
+ break;
+ }
+
+ return val;
+}
+
+WRITE16_MEMBER(spg2xx_sysdma_device::dma_w)
+{
+ offset &= 0x3;
+
+ switch (offset)
+ {
+ case 0x000: // DMA Source (lo)
+ LOGMASKED(LOG_DMA, "dma_w: DMA Source (lo) = %04x\n", data);
+ m_dma_regs[offset] = data;
+ break;
+
+ case 0x001: // DMA Source (hi)
+ LOGMASKED(LOG_DMA, "dma_w: DMA Source (hi) = %04x\n", data);
+ m_dma_regs[offset] = data;
+ break;
+
+ case 0x002: // DMA Length
+ LOGMASKED(LOG_DMA, "dma_w: DMA Length = %04x\n", data);
+ if (!(data & 0xc000)) // jak_dora writes 0xffff here which ends up trashing registers etc. why? such writes can't be valid
+ do_cpu_dma(data);
+ break;
+
+ case 0x003: // DMA Destination
+ LOGMASKED(LOG_DMA, "dma_w: DMA Dest = %04x\n", data);
+ m_dma_regs[offset] = data;
+ break;
+ }
+}
+
+void spg2xx_sysdma_device::do_cpu_dma(uint32_t len)
+{
+ address_space &mem = m_cpu->space(AS_PROGRAM);
+
+ uint32_t src = ((m_dma_regs[0x001] & 0x3f) << 16) | m_dma_regs[0x000];
+ uint32_t dst = m_dma_regs[0x003] & 0x3fff;
+
+ for (uint32_t j = 0; j < len; j++)
+ {
+ mem.write_word((dst + j) & 0x3fff, mem.read_word(src + j));
+ }
+
+ src += len;
+ m_dma_regs[0x000] = (uint16_t)src;
+ m_dma_regs[0x001] = (src >> 16) & 0x3f;
+ m_dma_regs[0x002] = 0;
+ m_dma_regs[0x003] = (dst + len) & 0x3fff;
+}