Method pad_until

perfect/src/asm.rs:259–295

Pad with NOP (up to the 8-byte encoding) until the requested address. Returns the number of emitted bytes.

(&mut self, addr: usize)

    /// Pad with NOP (up to the 8-byte encoding) until the requested address. 
    /// Returns the number of emitted bytes. 
    pub fn pad_until(&mut self, addr: usize) -> usize {
        if self.cur_addr() == addr { 
            return 0;
        }

        assert!(addr > self.cur_addr(),
            "Requested pad target {:016x} must be > cursor {:016x}",
            addr, self.cur_addr(),
        );
        assert!(addr <= self.max_addr(),
            "Requested {:016x} must be <= max addr {:016x}",
            addr, self.max_addr(),
        );

        let mut count = 0;
        let num_padding = addr - self.cur_addr();
        let nop8_count = num_padding / 8;
        let rem8 = num_padding % 8;
        for _ in 0..nop8_count {
            dynasm!(self ; .bytes NOP8);
            count += 8;
        }
        match rem8 {
            0 => {},
            1 => dynasm!(self ; nop),
            2 => dynasm!(self ; .bytes NOP2),
            3 => dynasm!(self ; .bytes NOP3),
            4 => dynasm!(self ; .bytes NOP4),
            5 => dynasm!(self ; .bytes NOP5),
            6 => dynasm!(self ; .bytes NOP6),
            7 => dynasm!(self ; .bytes NOP7),
            _ => unreachable!(),
        }
        count += rem8;
        assert_eq!(self.cur_addr(), addr);
        return count;
    }

    /// Write assembler to backing memory.
    pub fn commit(&mut self) -> Result<(), &str> {