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DSP: update docs for lrs/srs

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git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@3528 8ced0084-cf51-0410-be5f-012b33b47a6e
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hrydgard 2009-06-21 13:39:48 +00:00
parent f6ebaae792
commit c306374577
1 changed files with 6 additions and 13 deletions
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19
Source/Core/DSPCore/Src/DspIntLoadStore.cpp
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@ -26,32 +26,25 @@ namespace DSPInterpreter {
// SRS @M, $(0x18+S)
// 0010 1sss mmmm mmmm
// Store value from register $(0x18+S) to a memory pointed by address M.
// (8-bit sign extended).
// ALTERNATIVELY: It now seems that the upper 8 bits are controlled
// by CR, not sign extension.
// FIXME: Perform additional operation depending on destination register.
// Move value from register $(0x18+D) to data memory pointed by address CR[0-7] | M.
// That is, the upper 8 bits of the address are the bottom 8 bits from CR, and the
// lower 8 bits are from the 8-bit immediate.
// Note: pc+=2 in duddie's doc seems wrong
void srs(const UDSPInstruction& opc)
{
u8 reg = ((opc.hex >> 8) & 0x7) + 0x18;
// u16 addr = (u16)(s16)(s8)opc.hex;
u16 addr = (g_dsp.r[DSP_REG_CR] << 8) | (opc.hex & 0xFF);
dsp_dmem_write(addr, g_dsp.r[reg]);
}
// LRS $(0x18+D), @M
// 0010 0ddd mmmm mmmm
// Move value from data memory pointed by address M (8-bit sign
// extended) to register $(0x18+D).
// ALTERNATIVELY: It now seems that the upper 8 bits are controlled
// by CR, not sign extension.
// FIXME: Perform additional operation depending on destination register.
// Note: pc+=2 in duddie's doc seems wrong
// Move value from data memory pointed by address CR[0-7] | M to register $(0x18+D).
// That is, the upper 8 bits of the address are the bottom 8 bits from CR, and the
// lower 8 bits are from the 8-bit immediate.
void lrs(const UDSPInstruction& opc)
{
u8 reg = ((opc.hex >> 8) & 0x7) + 0x18;
//u16 addr = (u16)(s16)(s8)opc.hex;
u16 addr = (g_dsp.r[DSP_REG_CR] << 8) | (opc.hex & 0xFF);
g_dsp.r[reg] = dsp_dmem_read(addr);
}