millfork/docs/abi/generated-labels.md

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Guide to generated label names

Many Millfork constructs generate labels. Knowing what they mean can be useful when reading the generated assembly code.

Every generated label is of form .xx__11111 where 11111 is a sequential number and xx is the type:

• ah – optimized addition of carry

• an – logical conjunction short-circuiting

• bc – array bounds checking (-fbounds-checking)

• c8 – constant #8 for BIT when immediate addressing is not available

• co – greater-than comparison

• cp – equality comparison for larger types

• dd – labels renamed by code deduplication

• de – decrement for larger types

• do – beginning of a do-while statement

• ds – decimal right shift operation

• el – beginning of the "else" block in an if statement

• ew – end of a while statement

• fi – end of an if statement

• he – beginning of the body of a while statement

• in – increment for larger types

• is – optimized addition of carry using undocumented instructions

• lj – extra labels generated when converting invalid short jumps to long jumps

• me – start of a for loop doing bulk memory operations

• ms – bulk memory operations

• no – nonet to word extension caused by the nonet operator

• od – end of a do-while statement

• or – logical alternative short-circuiting

• sx – sign extension, from a smaller signed type to a larger type

• th – beginning of the "then" block in an if statement

• to – end of a for-to loop

• ur – a copy due to loop unrolling

• wh – beginning of a while statement

• xc – automatically extracted subroutine of commonly repeating code