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/* SPDX-License-Identifier: Unlicense
*/
#include "vdp.hpp"
uint32_t VDP::Read(const uint32_t offset, const enum bitness bitness)
{
const uint32_t res{};
if (DEBUG_TRACE_VDP_ACCESS) {
printf(
"VDP r%d%s @0x%08x 0x%0*x\n",
bitness * 8,
(bitness <= 1 ? " " : ""),
base_address + offset,
bitness * 2,
res);
}
if (bitness == BITNESS_32) {
// TODO
} else if (bitness == BITNESS_16) {
// TODO
}
// Ignore 8-bit reads for now
return 0;
}
void VDP::Write(const uint32_t offset, const enum bitness bitness, const uint32_t value)
{
if (DEBUG_TRACE_VDP_ACCESS) {
printf(
"VDP w%d%s @0x%08x 0x%0*x",
bitness * 8,
(bitness <= 1 ? " " : ""),
base_address + offset,
bitness * 2,
value);
}
if (bitness == BITNESS_32) {
if (offset == 4 || offset == 6) {
writeControl((value >> 16) & 0xffff);
writeControl(value & 0xffff);
}
} else if (bitness == BITNESS_16) {
if (offset == 4 || offset == 6) {
writeControl(value & 0xffff);
}
}
if (DEBUG_TRACE_VDP_ACCESS) {
printf("\n");
}
// Ignore 8-bit writes for now
}
void VDP::writeControl(const uint16_t value)
{
if (((value >> 13) & 0x7) == 4) {
const uint8_t reg_num = (value >> 8) & 0x1f;
const uint8_t reg_val = value & 0xff;
if (DEBUG_TRACE_VDP_ACCESS) {
printf(": reg 0x%02x w 0x%02x", reg_num, reg_val);
}
_reg[reg_num] = reg_val;
}
}
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