1 /*****************************************************************************/
5 /* Paravirtualization for the sim65 6502 simulator */
9 /* (C) 2013-2013 Ullrich von Bassewitz */
10 /* Römerstrasse 52 */
11 /* D-70794 Filderstadt */
12 /* EMail: uz@cc65.org */
15 /* This software is provided 'as-is', without any expressed or implied */
16 /* warranty. In no event will the authors be held liable for any damages */
17 /* arising from the use of this software. */
19 /* Permission is granted to anyone to use this software for any purpose, */
20 /* including commercial applications, and to alter it and redistribute it */
21 /* freely, subject to the following restrictions: */
23 /* 1. The origin of this software must not be misrepresented; you must not */
24 /* claim that you wrote the original software. If you use this software */
25 /* in a product, an acknowledgment in the product documentation would be */
26 /* appreciated but is not required. */
27 /* 2. Altered source versions must be plainly marked as such, and must not */
28 /* be misrepresented as being the original software. */
29 /* 3. This notice may not be removed or altered from any source */
32 /*****************************************************************************/
40 # define O_INITIAL O_BINARY
45 /* Microsoft compiler */
64 /*****************************************************************************/
66 /*****************************************************************************/
70 typedef void (*PVFunc) (CPURegs* Regs);
72 static unsigned ArgStart;
76 /*****************************************************************************/
78 /*****************************************************************************/
82 static unsigned GetAX (CPURegs* Regs)
84 return Regs->AC + (Regs->XR << 8);
89 static void SetAX (CPURegs* Regs, unsigned Val)
91 Regs->AC = Val & 0xFF;
98 static void MemWriteWord (unsigned Addr, unsigned Val)
100 MemWriteByte (Addr, Val);
102 MemWriteByte (Addr + 1, Val);
107 static unsigned char Pop (CPURegs* Regs)
109 return MemReadByte (0x0100 + ++Regs->SP);
114 static unsigned PopParam (unsigned char Incr)
116 unsigned SP = MemReadZPWord (0x00);
117 unsigned Val = MemReadWord (SP);
118 MemWriteWord (0x0000, SP + Incr);
124 static void PVArgs (CPURegs* Regs)
126 unsigned ArgC = ArgCount - ArgStart;
127 unsigned ArgV = GetAX (Regs);
128 unsigned SP = MemReadZPWord (0x00);
129 unsigned Args = SP - (ArgC + 1) * 2;
131 Print (stderr, 2, "PVArgs ($%04X)\n", ArgV);
133 MemWriteWord (ArgV, Args);
136 while (ArgStart < ArgCount) {
138 const char* Arg = ArgVec[ArgStart++];
139 SP -= strlen (Arg) + 1;
141 MemWriteByte (SP + I, Arg[I]);
145 MemWriteWord (Args, SP);
148 MemWriteWord (Args, 0x0000);
150 MemWriteWord (0x0000, SP);
156 static void PVExit (CPURegs* Regs)
158 Print (stderr, 1, "PVExit ($%02X)\n", Regs->AC);
165 static void PVOpen (CPURegs* Regs)
168 int OFlag = O_INITIAL;
169 unsigned RetVal, I = 0;
171 unsigned Mode = PopParam (Regs->YR - 4);
172 unsigned Flags = PopParam (2);
173 unsigned Name = PopParam (2);
176 Path[I] = MemReadByte (Name++);
180 Print (stderr, 2, "PVOpen (\"%s\", $%04X)\n", Path, Flags);
182 switch (Flags & 0x03) {
206 /* Avoid gcc warning */
209 RetVal = open (Path, OFlag);
211 SetAX (Regs, RetVal);
216 static void PVClose (CPURegs* Regs)
220 unsigned FD = GetAX (Regs);
222 Print (stderr, 2, "PVClose ($%04X)\n", FD);
226 SetAX (Regs, RetVal);
231 static void PVRead (CPURegs* Regs)
234 unsigned RetVal, I = 0;
236 unsigned Count = GetAX (Regs);
237 unsigned Buf = PopParam (2);
238 unsigned FD = PopParam (2);
240 Print (stderr, 2, "PVRead ($%04X, $%04X, $%04X)\n", FD, Buf, Count);
242 Data = xmalloc (Count);
244 RetVal = read (FD, Data, Count);
246 if (RetVal != (unsigned) -1) {
248 MemWriteByte (Buf++, Data[I++]);
253 SetAX (Regs, RetVal);
258 static void PVWrite (CPURegs* Regs)
261 unsigned RetVal, I = 0;
263 unsigned Count = GetAX (Regs);
264 unsigned Buf = PopParam (2);
265 unsigned FD = PopParam (2);
267 Print (stderr, 2, "PVWrite ($%04X, $%04X, $%04X)\n", FD, Buf, Count);
269 Data = xmalloc (Count);
271 Data[I++] = MemReadByte (Buf++);
274 RetVal = write (FD, Data, Count);
278 SetAX (Regs, RetVal);
283 static const PVFunc Hooks[] = {
294 void ParaVirtInit (unsigned aArgStart)
295 /* Initialize the paravirtualization subsystem */
297 ArgStart = aArgStart;
302 void ParaVirtHooks (CPURegs* Regs)
303 /* Potentially execute paravirtualization hooks */
305 /* Check for paravirtualization address range */
306 if (Regs->PC < 0xFFF0 ||
307 Regs->PC >= 0xFFF0 + sizeof (Hooks) / sizeof (Hooks[0])) {
311 /* Call paravirtualization hook */
312 Hooks[Regs->PC - 0xFFF0] (Regs);
315 Regs->PC = Pop(Regs) + (Pop(Regs) << 8) + 1;