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 /*****************************************************************************/
41 # define O_INITIAL O_BINARY
46 /* Microsoft compiler */
53 # define S_IREAD S_IRUSR
56 # define S_IWRITE S_IWUSR
71 /*****************************************************************************/
73 /*****************************************************************************/
77 typedef void (*PVFunc) (CPURegs* Regs);
79 static unsigned ArgStart;
83 /*****************************************************************************/
85 /*****************************************************************************/
89 static unsigned GetAX (CPURegs* Regs)
91 return Regs->AC + (Regs->XR << 8);
96 static void SetAX (CPURegs* Regs, unsigned Val)
98 Regs->AC = Val & 0xFF;
105 static void MemWriteWord (unsigned Addr, unsigned Val)
107 MemWriteByte (Addr, Val);
109 MemWriteByte (Addr + 1, Val);
114 static unsigned char Pop (CPURegs* Regs)
116 return MemReadByte (0x0100 + ++Regs->SP);
121 static unsigned PopParam (unsigned char Incr)
123 unsigned SP = MemReadZPWord (0x00);
124 unsigned Val = MemReadWord (SP);
125 MemWriteWord (0x0000, SP + Incr);
131 static void PVArgs (CPURegs* Regs)
133 unsigned ArgC = ArgCount - ArgStart;
134 unsigned ArgV = GetAX (Regs);
135 unsigned SP = MemReadZPWord (0x00);
136 unsigned Args = SP - (ArgC + 1) * 2;
138 Print (stderr, 2, "PVArgs ($%04X)\n", ArgV);
140 MemWriteWord (ArgV, Args);
143 while (ArgStart < ArgCount) {
145 const char* Arg = ArgVec[ArgStart++];
146 SP -= strlen (Arg) + 1;
148 MemWriteByte (SP + I, Arg[I]);
152 MemWriteWord (Args, SP);
155 MemWriteWord (Args, 0x0000);
157 MemWriteWord (0x0000, SP);
163 static void PVExit (CPURegs* Regs)
165 Print (stderr, 1, "PVExit ($%02X)\n", Regs->AC);
167 Print (stdout, 0, "%lu cycles\n", GetCycles ());
175 static void PVOpen (CPURegs* Regs)
178 int OFlag = O_INITIAL;
180 unsigned RetVal, I = 0;
182 unsigned Mode = PopParam (Regs->YR - 4);
183 unsigned Flags = PopParam (2);
184 unsigned Name = PopParam (2);
186 if (Regs->YR - 4 < 2) {
187 /* If the caller didn't supply the mode
188 ** argument, use a reasonable default.
194 Path[I] = MemReadByte (Name++);
198 Print (stderr, 2, "PVOpen (\"%s\", $%04X)\n", Path, Flags);
200 switch (Flags & 0x03) {
231 RetVal = open (Path, OFlag, OMode);
233 SetAX (Regs, RetVal);
238 static void PVClose (CPURegs* Regs)
242 unsigned FD = GetAX (Regs);
244 Print (stderr, 2, "PVClose ($%04X)\n", FD);
248 SetAX (Regs, RetVal);
253 static void PVRead (CPURegs* Regs)
256 unsigned RetVal, I = 0;
258 unsigned Count = GetAX (Regs);
259 unsigned Buf = PopParam (2);
260 unsigned FD = PopParam (2);
262 Print (stderr, 2, "PVRead ($%04X, $%04X, $%04X)\n", FD, Buf, Count);
264 Data = xmalloc (Count);
266 RetVal = read (FD, Data, Count);
268 if (RetVal != (unsigned) -1) {
270 MemWriteByte (Buf++, Data[I++]);
275 SetAX (Regs, RetVal);
280 static void PVWrite (CPURegs* Regs)
283 unsigned RetVal, I = 0;
285 unsigned Count = GetAX (Regs);
286 unsigned Buf = PopParam (2);
287 unsigned FD = PopParam (2);
289 Print (stderr, 2, "PVWrite ($%04X, $%04X, $%04X)\n", FD, Buf, Count);
291 Data = xmalloc (Count);
293 Data[I++] = MemReadByte (Buf++);
296 RetVal = write (FD, Data, Count);
300 SetAX (Regs, RetVal);
305 static const PVFunc Hooks[] = {
316 void ParaVirtInit (unsigned aArgStart)
317 /* Initialize the paravirtualization subsystem */
319 ArgStart = aArgStart;
324 void ParaVirtHooks (CPURegs* Regs)
325 /* Potentially execute paravirtualization hooks */
327 /* Check for paravirtualization address range */
328 if (Regs->PC < 0xFFF0 ||
329 Regs->PC >= 0xFFF0 + sizeof (Hooks) / sizeof (Hooks[0])) {
333 /* Call paravirtualization hook */
334 Hooks[Regs->PC - 0xFFF0] (Regs);
337 Regs->PC = Pop(Regs) + (Pop(Regs) << 8) + 1;