Changes 2024-01-17

Module TextIO

• Simplified Writer: no putChar procedure variable anymore, all output to be done using putString.
• Output via strings in lieu of repeatedly using single character output allows to make better use of buffers, such as the UART’s FIFO, and is friendlier for DMA.
• Texts.Write was the only procedure anyway that used single the char putChar procedure.

Module UART

• Renamed to UARTstr: uses the UART for string output, via device module UARTd.
• Removed procedure PutChar, since it’s not needed anymore for TextIO.Writer.
• Removed procedure GetChar, since it’s not needed anymore for TextIO.Reader.
• Note: procedure GetString needs implementation.

Module Terminals

• Terminals.Open does not directly use module UART (now UARTstr) anymore, but takes the putString and getString as parameters.
• This allows to “plug” other procedures from other modules, such as the new ones for the kernel, which avoid busy waiting (see UARTkstr below).

Module Texts

• Adjusted Texts.Write to simplified TextIO.Writer.

Module Main

• Implemented changes to module Terminals.

Module Kernel (v1)

• Added procedure Kernel.AwaitDeviceSet.
• Extended scheduler for Kernel.AwaitDeviceSet.
• Threads can enquire their last scheduler trigger: period, delay, or device.
• See new example NoBusyWaiting.

Module UARTkstr (for Kernel v1)

• New module.
• Equivalent to UARTstr, but without busy-waiting.
• The thread gets suspended until the transmit buffer is empty again.

Example program NoBusyWaiting

• New example program.
• Demo the new Kernel.AwaitDeviceSet and UARTkstr.