diff options
Diffstat (limited to 'man/as86.1')
| -rw-r--r-- | man/as86.1 | 21 |
1 files changed, 13 insertions, 8 deletions
@@ -83,17 +83,22 @@ a valid instruction) only put global symbols in object or symbol file .TP .B -j -replace short jumps that don't reach with 5 byte sequences, this causes the -assembler to add an extra pass to try to determine if the long jump is -really needed. If you add a second -.B -j -the assembler will keep adding passes until the labels all stabilise (to -a maximum of 30 passes) -Don't use this with hand written assembler use the explicit +replace all short jumps with similar 16 or 32 bit jumps, the 16 bit +conditional branches are encoded as a short conditional and a long +unconditional branch. +.TP +.B -O +this causes the assembler to add extra passes to try to use forward +references to reduce the bytes needed for some instructions. +If the labels move on the last pass the assembler will keep adding passes +until the labels all stabilise (to a maximum of 30 passes) +It's probably not a good idea to use this with hand written assembler +use the explicit .B br\ bmi\ bcc style opcodes for 8086 code or the .B jmp\ near -style for conditional i386 instructions. +style for conditional i386 instructions and make sure all variables are +defined before they are used. .TP .B -l produce list file, filename may follow |