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boundary="_000_PH8PR11MB68563E2FBD725A773B6ABF6583AD9PH8PR11MB6856namp_" --_000_PH8PR11MB68563E2FBD725A773B6ABF6583AD9PH8PR11MB6856namp_ Content-Type: text/plain; charset="koi8-r" Content-Transfer-Encoding: quoted-printable The library caller could call Poll() first, then call Read(), and the expec= tation is the char won't be lost. SBI doesn't have a poll call itself, so b= est you could do is read and stash. So you have to stash it globally. And r= ead must use the stashed char, if it exists, before requesting more data fr= om SBI. At that point, reading is easy to treat as continued polling - just= to keep the code simple. A ________________________________ =EF=D4: Gerd Hoffmann =EF=D4=D0=D2=C1=D7=CC=C5=CE=CF: Wednesday, March 1, 2023 2:13:32 AM =EB=CF=CD=D5: devel@edk2.groups.io ; Warkentin, Andre= i =EB=CF=D0=C9=D1: Daniel Schaefer ; Sunil V L =F4=C5=CD=C1: Re: [edk2-devel] [edk2 2/2] MdePkg: add BaseSerialPortLibRisc= VSbi Hi, > + while ((Index < NumberOfBytes) && SerialPortPoll ()) { > + Buffer[Index++] =3D (UINT8)mLastGetChar; > + mLastGetChar =3D -1; > + } Why do you use a global variable to pass the character? SerialPortPoll could just return it directly ... take care, Gerd --_000_PH8PR11MB68563E2FBD725A773B6ABF6583AD9PH8PR11MB6856namp_ Content-Type: text/html; charset="koi8-r" Content-Transfer-Encoding: quoted-printable
The library caller could call Poll() first, then call Read= (), and the expectation is the char won't be lost. SBI doesn't have a poll = call itself, so best you could do is read and stash. So you have to stash i= t globally. And read must use the stashed char, if it exists, before requesting more data from SBI. At that = point, reading is easy to treat as continued polling - just to keep the cod= e simple.

A
=EF=D4: Gerd Hoffmann <k= raxel@redhat.com>
=EF=D4=D0=D2=C1=D7=CC=C5=CE=CF: Wednesday, March 1, 2023 2:13:32 AM<= br> =EB=CF=CD=D5: devel@edk2.groups.io <devel@edk2.groups.io>; War= kentin, Andrei <andrei.warkentin@intel.com>
=EB=CF=D0=C9=D1: Daniel Schaefer <git@danielschaefer.me>; Suni= l V L <sunilvl@ventanamicro.com>
=F4=C5=CD=C1: Re: [edk2-devel] [edk2 2/2] MdePkg: add BaseSerialPort= LibRiscVSbi
 
  Hi,

> +  while ((Index < NumberOfBytes) && SerialPortPoll ()= ) {
> +    Buffer[Index++] =3D (UINT8)mLastGetChar;
> +    mLastGetChar    =3D -1;
> +  }

Why do you use a global variable to pass the character?  SerialPortPol= l
could just return it directly ...

take care,
  Gerd

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