Reader for bit range [0:0] incorrect

[robamu]

I am working on a HAL implementation for a UART peripheral and came cross odd behaviour:

            ...
            if status_reader.rdavl().bit_is_set() {
                let data = uart.data.read().bits();
                Ok((data & 0xff) as u8)
            } else {
                Err(nb::Error::WouldBlock)
            }
            ...

The rdavl().bit_is_set() call always returns true, even when the actual bit in the hardware was not set (I checked in peripheral view and by reading the whole register value as u32).

I then checked the rdavl() code in the PAC:

impl R {
    #[doc = "Bit 0 - Read Data Available"]
    #[inline(always)]
    pub fn rdavl(&self) -> RDAVL_R {
        RDAVL_R::new(self.bits != 0)
    }
    #[doc = "Bit 1 - Read Fifo NOT Full"]
    #[inline(always)]
    pub fn rdnfull(&self) -> RDNFULL_R {
        RDNFULL_R::new(((self.bits >> 1) & 0x01) != 0)
    }
    #[doc = "Bit 2 - RX Busy Receiving"]
    #[inline(always)]
    pub fn rxbusy(&self) -> RXBUSY_R {
        RXBUSY_R::new(((self.bits >> 2) & 0x01) != 0)
    }

This is odd. The call does not look correct, it should be RDAVL_R::new((self.bits & 0x01) != 0)

I checked the SVD file:

          <name>RXSTATUS</name>
          <description>Status Register</description>
          <addressOffset>0x010</addressOffset>
          <access>read-only</access>
          <resetValue>0x0000000</resetValue>
          <fields>
            <field>
              <name>RDAVL</name>
              <description>Read Data Available</description>
              <bitRange>[0:0]</bitRange>
            </field>
            <field>
              <name>RDNFULL</name>
              <description>Read Fifo NOT Full</description>
              <bitRange>[1:1]</bitRange>
            </field>

Might this be a bug?

[burrbull]

Yes, looks like a bug

[burrbull]

Can you check previous versions to find causer?

[robamu]

Yes

[robamu]

Oh, I actually need another SVD sample file now because the one I always used of course does not work with an older version

[burrbull]

The problem is after #537

[burrbull]

#549

[robamu]

Okay, thanks. I just tried out the program on the SVD sample file : https://www.keil.com/pack/doc/CMSIS/SVD/html/svd_Example_pg.html .
The bit mask works there (SR timer register bit 0) . Maybe it has to do something with the size field missing from the register?