void dsp16_device::execute_run()
{
// HACK TO MAKE CPU DO NOTHING.
// REMOVE IF DEVELOPING CPU CORE.
m_icount = 0;
return;
do
{
// debugging
m_ppc = m_pc; // copy PC to previous PC
debugger_instruction_hook(this, m_pc);
// instruction fetch & execute
UINT8 cycles;
UINT8 pcAdvance;
const UINT16 op = opcode_read();
execute_one(op, cycles, pcAdvance);
// step
m_pc += pcAdvance;
m_icount -= cycles;
// The 16 bit PI "shadow" register gets set to PC on each instruction except
// when an interrupt service routine is active (TODO: Interrupt check) (page 2-4)
m_pi = m_pc;
} while (m_icount > 0);
}
void dsp16_device::execute_one(const UINT16& op, UINT8& cycles, UINT8& pcAdvance)
{
cycles = 1;
pcAdvance = 0;
const UINT8 opcode = (op >> 11) & 0x1f;
switch(opcode)
{
// Format 1: Multiply/ALU Read/Write Group
case 0x06:
{
// F1, Y : (page 3-38)
const UINT8 Y = (op & 0x000f);
const UINT8 S = (op & 0x0200) >> 9;
const UINT8 D = (op & 0x0400) >> 10;
const UINT8 F1 = (op & 0x01e0) >> 5;
executeF1Field(F1, D, S);
executeYFieldPost(Y);
cycles = 1;
pcAdvance = 1;
break;
}
case 0x04:
case 0x1c:
{
// F1 Y=a0[1] | F1 Y=a1[1]
//const UINT8 Y = (op & 0x000f);
//const UINT8 S = (op & 0x0200) >> 9;
//const UINT8 D = (op & 0x0400) >> 10;
//const UINT8 F1 = (op & 0x01e0) >> 5;
break;
}
case 0x16:
{
// F1, x = Y
//const UINT8 Y = (op & 0x000f);
//const UINT8 S = (op & 0x0200) >> 9;
//const UINT8 D = (op & 0x0400) >> 10;
//const UINT8 F1 = (op & 0x01e0) >> 5;
break;
}
case 0x17:
{
// F1, y[l] = Y : (page 3-44)
const UINT8 Y = (op & 0x000f);
const UINT8 X = (op & 0x0010) >> 4;
const UINT8 S = (op & 0x0200) >> 9;
const UINT8 D = (op & 0x0400) >> 10;
const UINT8 F1 = (op & 0x01e0) >> 5;
executeF1Field(F1, D, S);
UINT16* sourceReg = (UINT16*)registerFromYFieldUpper(Y);
UINT16 sourceValue = data_read(*sourceReg);
switch (X)
{
case 0x00:
writeRegister(addressYL(), sourceValue);
break;
case 0x01:
writeRegister(&m_y, sourceValue);
break;
default:
break;
}
executeYFieldPost(Y);
cycles = 1;
pcAdvance = 1;
break;
}
case 0x1f:
{
// F1, y = Y, x = *pt++[i]
//const UINT8 Y = (op & 0x000f);
//const UINT8 X = (op & 0x0010) >> 4;
//const UINT8 S = (op & 0x0200) >> 9;
//const UINT8 D = (op & 0x0400) >> 10;
//const UINT8 F1 = (op & 0x01e0) >> 5;
break;
}
case 0x19:
case 0x1b:
{
// F1, y = a0|1, x = *pt++[i]
//const UINT8 Y = (op & 0x000f);
//const UINT8 X = (op & 0x0010) >> 4;
//const UINT8 S = (op & 0x0200) >> 9;
//const UINT8 D = (op & 0x0400) >> 10;
//const UINT8 F1 = (op & 0x01e0) >> 5;
break;
}
case 0x14:
{
// F1, Y = y[1] : (page 3-53)
const UINT8 Y = (op & 0x000f);
const UINT8 X = (op & 0x0010) >> 4;
const UINT8 S = (op & 0x0200) >> 9;
const UINT8 D = (op & 0x0400) >> 10;
const UINT8 F1 = (op & 0x01e0) >> 5;
executeF1Field(F1, D, S);
UINT16* destinationReg = (UINT16*)registerFromYFieldUpper(Y);
UINT16 yRegValue = 0x0000;
switch (X)
{
case 0x00:
yRegValue = (m_y & 0x0000ffff);
break;
case 0x01:
yRegValue = (m_y & 0xffff0000) >> 16;
break;
default:
break;
}
data_write(*destinationReg, yRegValue);
executeYFieldPost(Y);
cycles = 2;
pcAdvance = 1;
break;
}
// Format 1a: Multiply/ALU Read/Write Group (TODO: Figure out major typo in docs on p3-51)
case 0x07:
{
// F1, At[1] = Y : (page 3-50)
const UINT8 Y = (op & 0x000f);
const UINT8 S = (op & 0x0200) >> 9;
const UINT8 aT = (op & 0x0400) >> 10;
const UINT8 F1 = (op & 0x01e0) >> 5;
executeF1Field(F1, !aT, S);
UINT64* destinationReg = NULL;
switch(aT)
{
case 0:
destinationReg = &m_a1;
break;
case 1:
destinationReg = &m_a0;
break;
default:
break;
}
UINT16 sourceAddress = *((UINT16*)registerFromYFieldUpper(Y));
INT64 sourceValueSigned = (INT16)data_read(sourceAddress);
*destinationReg = sourceValueSigned & U64(0xffffffffff);
executeYFieldPost(Y);
cycles = 1;
pcAdvance = 1;
break;
}
// Format 2: Multiply/ALU Read/Write Group
case 0x15:
{
// F1, Z : y[1]
//const UINT8 Z = (op & 0x000f);
//const UINT8 X = (op & 0x0010) >> 4;
//const UINT8 S = (op & 0x0200) >> 9;
//const UINT8 D = (op & 0x0400) >> 10;
//const UINT8 F1 = (op & 0x01e0) >> 5;
break;
}
case 0x1d:
{
// F1, Z : y, x=*pt++[i]
//const UINT8 Z = (op & 0x000f);
//const UINT8 X = (op & 0x0010) >> 4;
//const UINT8 S = (op & 0x0200) >> 9;
//const UINT8 D = (op & 0x0400) >> 10;
//const UINT8 F1 = (op & 0x01e0) >> 5;
break;
}
// Format 2a: Multiply/ALU Read/Write Group
case 0x05:
{
// F1, Z : aT[1]
//const UINT8 Z = (op & 0x000f);
//const UINT8 X = (op & 0x0010) >> 4;
//const UINT8 S = (op & 0x0200) >> 9;
//const UINT8 aT = (op & 0x0400) >> 10;
//const UINT8 F1 = (op & 0x01e0) >> 5;
break;
}
// Format 3: Special Functions
case 0x12:
case 0x13:
{
// if|ifc CON F2
//const UINT8 CON = (op & 0x001f);
//const UINT8 S = (op & 0x0200) >> 9;
//const UINT8 D = (op & 0x0400) >> 10;
//const UINT8 F2 = (op & 0x01e0) >> 5;
break;
}
// Format 4: Branch Direct Group
case 0x00:
case 0x01:
{
// goto JA : (page 3-20)
const UINT16 JA = (op & 0x0fff) | (m_pc & 0xf000);
m_pc = JA;
cycles = 2;
pcAdvance = 0;
break;
}
case 0x10:
case 0x11:
{
// call JA : (page 3-23)
const UINT16 JA = (op & 0x0fff) | (m_pc & 0xf000);
m_pr = m_pc + 1;
m_pc = JA;
cycles = 2;
pcAdvance = 0;
break;
}
// Format 5: Branch Indirect Group
case 0x18:
{
// goto B
//const UINT8 B = (op & 0x0700) >> 8;
break;
}
// Format 6: Contitional Branch Qualifier/Software Interrupt (icall)
case 0x1a:
{
// if CON [goto/call/return]
//const UINT8 CON = (op & 0x001f);
break;
}
// Format 7: Data Move Group
case 0x09:
case 0x0b:
{
// R = aS
//const UINT8 R = (op & 0x03f0) >> 4;
//const UINT8 S = (op & 0x1000) >> 12;
break;
}
case 0x08:
{
// aT = R
//const UINT8 R = (op & 0x03f0) >> 4;
//const UINT8 aT = (op & 0x0400) >> 10;
break;
}
case 0x0f:
{
// R = Y
//const UINT8 Y = (op & 0x000f);
//const UINT8 R = (op & 0x03f0) >> 4;
break;
}
case 0x0c:
{
// Y = R : (page 3-33)
const UINT8 Y = (op & 0x000f);
const UINT8 R = (op & 0x03f0) >> 4;
UINT16* destinationReg = (UINT16*)registerFromYFieldUpper(Y);
UINT16* sourceReg = (UINT16*)registerFromRTable(R);
data_write(*destinationReg, *sourceReg);
executeYFieldPost(Y);
cycles = 2;
pcAdvance = 1;
break;
}
case 0x0d:
{
// Z : R
//const UINT8 Z = (op & 0x000f);
//const UINT8 R = (op & 0x03f0) >> 4;
break;
}
// Format 8: Data Move (immediate operand - 2 words)
case 0x0a:
{
// R = N : (page 3-28)
const UINT8 R = (op & 0x03f0) >> 4;
const UINT16 iVal = opcode_read(1);
void* reg = registerFromRTable(R);
writeRegister(reg, iVal);
cycles = 2;
pcAdvance = 2;
break;
}
// Format 9: Short Immediate Group
case 0x02:
case 0x03:
{
// R = M : (page 3-27)
const INT8 M = (op & 0x00ff);
const UINT8 R = (op & 0x0e00) >> 9;
void* reg = registerFromRImmediateField(R);
writeRegister(reg, (INT16)M); // Sign extend 8 bit int
cycles = 1;
pcAdvance = 1;
break;
}
// Format 10: do - redo
case 0x0e:
{
// do|redo K : (pages 3-25 & 3-26)
const UINT8 K = (op & 0x007f);
const UINT8 NI = (op & 0x0780) >> 7;
if (NI != 0)
{
// Do
m_cacheStart = m_pc + 1;
m_cacheEnd = m_pc + NI + 1;
m_cacheIterations = K-1; // -1 because we check the counter below
cycles = 1;
pcAdvance = 1;
}
else
{
// Redo
m_cacheIterations = K-1; // -1 because we check the counter below
m_cacheRedoNextPC = m_pc + 1;
m_pc = m_cacheStart;
pcAdvance = 0;
cycles = 2;
pcAdvance = 1;
}
break;
}
// RESERVED
case 0x1e:
{
break;
}
// UNKNOWN
default:
{
break;
}
}
// Handle end-of-cache conditions for do|redos
if (m_cacheIterations == 0 && m_cacheRedoNextPC != CACHE_INVALID)
{
// You've reached the end of a cache loop after a redo opcode.
m_pc = m_cacheRedoNextPC;
m_cacheRedoNextPC = CACHE_INVALID;
pcAdvance = 0;
}
if (m_cacheIterations > 0 && (m_pc+pcAdvance == m_cacheEnd))
{
// A regular iteration on a cached loop.
m_cacheIterations--;
m_pc = m_cacheStart;
pcAdvance = 0;
}
}