OSRDCH

Waits for a character from the current input stream.

Specification

6502	Z80	6809	PDP11	80x86	32016	ARM	RISC-V	On entry:	On exit:
A	A	A	R0	AL	R1	R0	A0	-	= byte read
									Cy=Error status

If an error occured (usually, Escape being pressed), then the carry flag is set on exit. If the error was Escape, then A will be &1B regardless of the defined Escape character.

Calling from BBC BASIC

• b%=GET calls OSRDCH.
• b$=GET$ calls OSRDCH.

Entry points

• BBC BASIC Entry Address: &FFE0
• 6502 Entry Address: &FFE0, vectors via &0210
• Z80 Entry Address: &FFE0, vectors via &FFE1
• 6809 Entry Address: &FFE0, vectors via &FFE1
• 80x86 Entry Address: INT &46, vectors via 0000:0118
• 32000 Entry Address: SVC &05
• PDP11 Entry Address: EMT 5, vector &05
• ARM Entry Address: SWI &04 "OS_ReadC", vector &04
• RISC-V Entry Address: ECALL &AC0005

Implementations

All MOSs implement OSRDCH. Some systems allow BGET#0 to read from the character input stream via OSRDCH.

Jgharston 17:02, 6 November 2009 (UTC)