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copied!<p>What architecture are you programming for? </p> <p>If you are writing a boot loader for x86, then your boot loader will at first be in 16 bit mode. Thus when the compiler issues a push instruction, which is how I would guess it passes the arguments for the printf() function, it will by default push 16 bits of data. The long data type will be a specially issued instruction (or two) to push all 32 bits onto the stack, this is assuming an int is 16 bits and a long is 32 bits (which for a 16bit mode compiler, is not an unreasonable assumption, I don't think).</p> <p>So, lets assume x86 in 16 bit mode:</p> <p>It would appear you are using *ip to address the arguments as they are pushed on the stack. Since ip is a pointer to a long (a 32 bit data type) when you do ip++ you are incrementing the actual value held by the pointer by 4, as in if *ip = 0x1234 then *(ip+1) = 0x1238. Thus if you are using ip++ for the 16bit ints, then you are skipping an int every time you do ip++, since ints are only 2 bytes (16 bits). A possible solution is to use void * for ip and then add sizeof(data type) to ip; i.e if you print an int, so an:</p> <pre><code>void *ip = &(fmt + 1); /* Skip over fmt. */ ... ip += sizeof(int); </code></pre> <p>Or for an unsigned long:</p> <pre><code>ip += sizeof(unsigned long); </code></pre> <p>However, without more specific details about the exact architecture you are programming for and and what ABI your compiler is using, I can only wildly speculate.</p> <p>I hope this helps.</p> <p>Regards, Alex</p>

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