[binutils-gdb] Tidy objdump opb expressions

[binutils-gdb] Tidy objdump opb expressions

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=170957ff9b847cf44f6121fd846f5483f2090afd

commit 170957ff9b847cf44f6121fd846f5483f2090afd
Author: Alan Modra <amodra@gmail.com>
Date:   Wed Apr 17 18:16:55 2024 +0930

    Tidy objdump opb expressions
    
    I don't think any of these can overflow, but since all of the
    expressions I'm editing here are inside a while loop with condition
    addr_offset < stop_offset, this change makes it more obvious that they
    can't overflow.
    
            * objdump.c (disassemble_bytes): Calculate octet expressions
            involving both addr_offset and stop_offset by first
            subtracting addr_offset from stop_offset.

Diff:
---
 binutils/objdump.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/binutils/objdump.c b/binutils/objdump.c
index 6396174d50f..f92e14b33e4 100644
--- a/binutils/objdump.c
+++ b/binutils/objdump.c
@@ -3356,28 +3356,28 @@ disassemble_bytes (struct disassemble_info *inf,
       /* If we see more than SKIP_ZEROES octets of zeroes, we just
 	 print `...'.  */
       if (! disassemble_zeroes)
-	for (; addr_offset * opb + octets < stop_offset * opb; octets++)
+	for (; octets < (stop_offset - addr_offset) * opb; octets++)
 	  if (data[addr_offset * opb + octets] != 0)
 	    break;
       if (! disassemble_zeroes
 	  && (inf->insn_info_valid == 0
 	      || inf->branch_delay_insns == 0)
 	  && (octets >= skip_zeroes
-	      || (addr_offset * opb + octets == stop_offset * opb
+	      || (octets == (stop_offset - addr_offset) * opb
 		  && octets < skip_zeroes_at_end)))
 	{
 	  /* If there are more nonzero octets to follow, we only skip
 	     zeroes in multiples of 4, to try to avoid running over
 	     the start of an instruction which happens to start with
 	     zero.  */
-	  if (addr_offset * opb + octets != stop_offset * opb)
+	  if (octets != (stop_offset - addr_offset) * opb)
 	    octets &= ~3;
 
 	  /* If we are going to display more data, and we are displaying
 	     file offsets, then tell the user how many zeroes we skip
 	     and the file offset from where we resume dumping.  */
 	  if (display_file_offsets
-	      && addr_offset + octets / opb < stop_offset)
+	      && octets / opb < stop_offset - addr_offset)
 	    printf (_("\t... (skipping %lu zeroes, "
 		      "resuming at file offset: 0x%lx)\n"),
 		    (unsigned long) (octets / opb),
@@ -3529,7 +3529,7 @@ disassemble_bytes (struct disassemble_info *inf,
 	      bfd_vma j;
 
 	      octets = octets_per_line;
-	      if (addr_offset + octets / opb > stop_offset)
+	      if (octets / opb > stop_offset - addr_offset)
 		octets = (stop_offset - addr_offset) * opb;
 
 	      for (j = addr_offset * opb; j < addr_offset * opb + octets; ++j)