MOVSX sign-extends its source (second) operand to the length of
its destination (first) operand, and copies the result into the
destination operand. MOVZX does the same, but zero-extends
rather than sign-extending.
movsxb
8086 and laterMove Data with Sign or Zero Extend
movsxb ax, al | movsxb reg16, r/m8 | movsxb reg32, r/m8 | movsxb reg64, r/m8Loading...
Forms
Every form of movsxb the assembler accepts.
| Form | Since | Notes |
|---|---|---|
| movsxb ax, al | 8086 | |
| movsxb reg16, r/m8 | 386 | |
| movsxb reg32, r/m8 | 386 | |
| movsxb reg64, r/m8 | x86-64 | long |