1 /*****************************************************************************/
5 /* Binary code management */
9 /* (C) 2000 Ullrich von Bassewitz */
11 /* D-70597 Stuttgart */
12 /* EMail: uz@musoftware.de */
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 /*****************************************************************************/
49 /*****************************************************************************/
51 /*****************************************************************************/
55 static unsigned char CodeBuf [0x10000]; /* Code buffer */
56 static unsigned long CodeStart; /* Start address */
57 static unsigned long CodeEnd; /* End address */
58 static unsigned long PC; /* Current PC */
62 /*****************************************************************************/
64 /*****************************************************************************/
68 void LoadCode (const char* Name, unsigned long StartAddress)
69 /* Load the code from the given file */
71 unsigned Count, MaxCount;
75 PRECONDITION (StartAddress < 0x10000);
77 /* Calculate the maximum code size */
78 MaxCount = 0x10000 - StartAddress;
81 F = fopen (Name, "rb");
83 Error ("Cannot open `%s': %s", Name, strerror (errno));
86 /* Read from the file and remember the number of bytes read */
87 Count = fread (CodeBuf + StartAddress, 1, MaxCount, F);
89 Error ("Error reading from `%s': %s", Name, strerror (errno));
92 Error ("File `%s' contains no data", Name);
95 /* Set the buffer variables */
96 CodeStart = PC = StartAddress;
97 CodeEnd = CodeStart + Count - 1; /* CodeEnd is inclusive */
102 unsigned GetPC (void)
103 /* Get the current program counter */
110 unsigned char PeekCodeByte (void)
111 /* Peek at the byte at the current PC */
113 PRECONDITION (PC <= CodeEnd);
119 unsigned char GetCodeByte (void)
120 /* Get a byte from the PC and increment it */
122 PRECONDITION (PC <= CodeEnd);
123 return CodeBuf [PC++];
128 unsigned GetCodeWord (void)
129 /* Get a word from the current PC and increment it */
131 unsigned Lo = GetCodeByte ();
132 unsigned Hi = GetCodeByte ();
133 return Lo | (Hi << 8);
138 unsigned GetRemainingBytes (void)
139 /* Return the number of remaining code bytes */
142 return (CodeEnd - PC + 1);
150 void ResetCode (void)
151 /* Reset the code input to start over for the next pass */