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 /* Microsoft compiler */
42 # pragma warning(disable : 4996)
43 # define O_INITIAL O_BINARY
62 /*****************************************************************************/
64 /*****************************************************************************/
68 typedef void (*PVFunc) (CPURegs* Regs);
70 static unsigned ArgStart;
74 /*****************************************************************************/
76 /*****************************************************************************/
80 static unsigned GetAX (CPURegs* Regs)
82 return Regs->AC + (Regs->XR << 8);
87 static void SetAX (CPURegs* Regs, unsigned Val)
89 Regs->AC = Val & 0xFF;
96 static void MemWriteWord (unsigned Addr, unsigned Val)
98 MemWriteByte (Addr, Val);
100 MemWriteByte (Addr + 1, Val);
105 static unsigned char Pop (CPURegs* Regs)
107 return MemReadByte (0x0100 + ++Regs->SP);
112 static unsigned PopParam (unsigned char Incr)
114 unsigned SP = MemReadZPWord (0x00);
115 unsigned Val = MemReadWord (SP);
116 MemWriteWord (0x0000, SP + Incr);
122 static void PVArgs (CPURegs* Regs)
124 unsigned ArgC = ArgCount - ArgStart;
125 unsigned ArgV = GetAX (Regs);
126 unsigned SP = MemReadZPWord (0x00);
127 unsigned Args = SP - (ArgC + 1) * 2;
129 Print (stdout, 2, "PVArgs ($%04X)\n", ArgV);
131 MemWriteWord (ArgV, Args);
134 while (ArgStart < ArgCount) {
136 const char* Arg = ArgVec[ArgStart++];
137 SP -= strlen (Arg) + 1;
139 MemWriteByte (SP + I, Arg[I]);
143 MemWriteWord (Args, SP);
146 MemWriteWord (Args, 0x0000);
148 MemWriteWord (0x0000, SP);
154 static void PVExit (CPURegs* Regs)
156 Print (stdout, 1, "PVExit ($%02X)\n", Regs->AC);
163 static void PVOpen (CPURegs* Regs)
166 int OFlag = O_INITIAL;
167 unsigned RetVal, I = 0;
169 unsigned Mode = PopParam (Regs->YR - 4);
170 unsigned Flags = PopParam (2);
171 unsigned Name = PopParam (2);
174 Path[I] = MemReadByte (Name++);
178 Print (stdout, 2, "PVOpen (\"%s\", $%04X)\n", Path, Flags);
180 switch (Flags & 0x03) {
204 /* Avoid gcc warning */
207 RetVal = open (Path, OFlag);
209 SetAX (Regs, RetVal);
214 static void PVClose (CPURegs* Regs)
218 unsigned FD = GetAX (Regs);
220 Print (stdout, 2, "PVClose ($%04X)\n", FD);
224 SetAX (Regs, RetVal);
229 static void PVRead (CPURegs* Regs)
232 unsigned RetVal, I = 0;
234 unsigned Count = GetAX (Regs);
235 unsigned Buf = PopParam (2);
236 unsigned FD = PopParam (2);
238 Print (stdout, 2, "PVRead ($%04X, $%04X, $%04X)\n", FD, Buf, Count);
240 Data = xmalloc (Count);
242 RetVal = read (FD, Data, Count);
244 if (RetVal != (unsigned) -1) {
246 MemWriteByte (Buf++, Data[I++]);
251 SetAX (Regs, RetVal);
256 static void PVWrite (CPURegs* Regs)
259 unsigned RetVal, I = 0;
261 unsigned Count = GetAX (Regs);
262 unsigned Buf = PopParam (2);
263 unsigned FD = PopParam (2);
265 Print (stdout, 2, "PVWrite ($%04X, $%04X, $%04X)\n", FD, Buf, Count);
267 Data = xmalloc (Count);
269 Data[I++] = MemReadByte (Buf++);
272 RetVal = write (FD, Data, Count);
276 SetAX (Regs, RetVal);
281 static const PVFunc Hooks[] = {
292 void ParaVirtInit (unsigned aArgStart)
293 /* Initialize the paravirtualization subsystem */
295 ArgStart = aArgStart;
300 void ParaVirtHooks (CPURegs* Regs)
301 /* Potentially execute paravirtualization hooks */
303 /* Check for paravirtualization address range */
304 if (Regs->PC < 0xFFF0 ||
305 Regs->PC >= 0xFFF0 + sizeof (Hooks) / sizeof (Hooks[0])) {
309 /* Call paravirtualization hook */
310 Hooks[Regs->PC - 0xFFF0] (Regs);
313 Regs->PC = Pop(Regs) + (Pop(Regs) << 8) + 1;