Added comments

[clinton/Virtual-Jaguar-Rx.git] / src / m68000 / m68kdasm.c

diff --git a/src/m68000/m68kdasm.c b/src/m68000/m68kdasm.c
index 7109163..8627806 100644 (file)
--- a/src/m68000/m68kdasm.c
+++ b/src/m68000/m68kdasm.c
@@ -318,6 +318,8 @@ void HandleMovem(char * output, uint16_t data, int direction)
 }
 
 
+// Disassemble the M68K line based on the address
+// Append, or not, the line with the ouput pointer and return the number of bytes
 unsigned int M68KDisassemble(char * output, uint32_t addr, unsigned int OpCodes)
 {
        char f[256], str[256];
@@ -335,26 +337,33 @@ unsigned int M68KDisassemble(char * output, uint32_t addr, unsigned int OpCodes)
        char instrname[20];
        const struct mnemolookup * lookup;
 
+       // get the opcode
        uint32_t opcode = get_iword_1(m68kpc_offset);
        m68kpc_offset += 2;
 
+       // replace an illegal opcode by the illegal opcode
        if (cpuFunctionTable[opcode] == IllegalOpcode)
                opcode = 0x4AFC;
 
+       // point on the opcode information
        struct instr * dp = table68k + opcode;
 
-       for(lookup=lookuptab; lookup->mnemo!=dp->mnemo; lookup++)
-               ;
-
+       // get the instruction name from the opcode
+       for(lookup=lookuptab; lookup->mnemo!=dp->mnemo; lookup++);
        strcpy(instrname, lookup->name);
+
+       // look for a branching instruction
        char * ccpt = strstr(instrname, "cc");
 
+       // correct branch naming
        if (ccpt)
                strncpy(ccpt, ccnames[dp->cc], 2);
 
+       // keep the instruction name
        sprintf(f, "%s", instrname);
        strcat(str, f);
 
+       // set instruction size
        switch (dp->size)
        {
        case sz_byte: strcat(str, ".B\t"); break;
@@ -363,16 +372,16 @@ unsigned int M68KDisassemble(char * output, uint32_t addr, unsigned int OpCodes)
        default: strcat(str, "\t"); break;
        }
 
-       // Get source and destination operands (if any)
+       // reset the buffers
        src[0] = dst[0] = f[0] = 0;
 
+       // get source operand in src
        if (dp->suse)
-               newpc = m68k_getpc() + m68kpc_offset
-                       + ShowEA(dp->mnemo, dp->sreg, dp->smode, dp->size, src);
+               newpc = m68k_getpc() + m68kpc_offset + ShowEA(dp->mnemo, dp->sreg, dp->smode, dp->size, src);
 
+       // get destination operand in dst
        if (dp->duse)
-               newpc = m68k_getpc() + m68kpc_offset
-                       + ShowEA(dp->mnemo, dp->dreg, dp->dmode, dp->size, dst);
+               newpc = m68k_getpc() + m68kpc_offset + ShowEA(dp->mnemo, dp->dreg, dp->dmode, dp->size, dst);
 
        // Handle execptions to the standard rules
        if (dp->mnemo == i_BSR || dp->mnemo == i_Bcc)
@@ -405,14 +414,8 @@ unsigned int M68KDisassemble(char * output, uint32_t addr, unsigned int OpCodes)
                strcat(output, f);
        }
 
-       if (OpCodes)
-       {
-               strcat(output, str);
-       }
-       else
-       {
-               strcpy(output, str);
-       }
+       // add the line to the output
+       OpCodes ? strcat(output, str) : strcpy(output, str);
 
        return numberOfBytes;
 }