Difference between revisions of "OSBGET"
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[[Category:MOS_API]] | [[Category:MOS_API]] | ||
| − | Read (get) a byte | + | {{PageTitle|OSBGET: Read (get) a byte}} |
==Specification== | ==Specification== | ||
| − | {| cellpadding="0" cellspacing="0" | + | {| cellpadding="0" cellspacing="0" border="1" |
| − | | | + | | 6502 || Z80 || 6809 || PDP11 || 80x86 || 32016 || ARM || 68000 || RISC-V || align="left" | '''On entry:''' || align="left" | '''On exit:''' |
|- align="center" valign="top" | |- align="center" valign="top" | ||
| − | | A || A || A || R0 || AL || R1 || R0 || align="left" | - || align="left" | = byte read | + | | A || A || A || R0 || AL || R1 || R0 || D0 || A0 || align="left" | - || align="left" | = byte read |
|- align="center" valign="top" | |- align="center" valign="top" | ||
| − | | Y || H || Y || R1 || BX || R2 || R1 || align="left" | = handle || align="left" | preserved | + | | Y || H || Y || R1 || BX || R2 || R1 || D1 || A1 || align="left" | = handle || align="left" | preserved |
|- align="center" valign="top" | |- align="center" valign="top" | ||
| − | | || || || || || || || align="left" | || align="left" | Cy=EOF status | + | | || || || || || || || || || align="left" | || align="left" | Cy=EOF status |
|} | |} | ||
| − | If the byte read is after the end of file, the carry flag is set on exit and the EOF-error-flag is set. | + | If the byte read is after the end of file, the carry flag is set on exit and the EOF-error-flag is set. After the EOF byte has been read, the next read produces an error. An error is generated if the object is a directory or doesn't have read access. |
==Calling from BBC BASIC== | ==Calling from BBC BASIC== | ||
| Line 30: | Line 30: | ||
* PDP-11 Entry Address: EMT 9, vector &09 | * PDP-11 Entry Address: EMT 9, vector &09 | ||
* ARM Entry Address: SWI &0A "OS_BGet", vector &0A | * ARM Entry Address: SWI &0A "OS_BGet", vector &0A | ||
| + | * 68000 Entry Address: MOV #&0A,A0:TRAP 12 | ||
| + | * RISC-V Entry Address: ECALL &AC0009 | ||
==Implementations== | ==Implementations== | ||
All filing systems implement OSBGET. | All filing systems implement OSBGET. | ||
| + | {{Filing}} | ||
[[User:Jgharston|Jgharston]] 16:56, 6 November 2009 (UTC) | [[User:Jgharston|Jgharston]] 16:56, 6 November 2009 (UTC) | ||
Latest revision as of 20:09, 17 September 2023
OSBGET: Read (get) a byte
Contents
Specification
| 6502 | Z80 | 6809 | PDP11 | 80x86 | 32016 | ARM | 68000 | RISC-V | On entry: | On exit: |
| A | A | A | R0 | AL | R1 | R0 | D0 | A0 | - | = byte read |
| Y | H | Y | R1 | BX | R2 | R1 | D1 | A1 | = handle | preserved |
| Cy=EOF status |
If the byte read is after the end of file, the carry flag is set on exit and the EOF-error-flag is set. After the EOF byte has been read, the next read produces an error. An error is generated if the object is a directory or doesn't have read access.
Calling from BBC BASIC
-
b%=BGET#chcalls OSBGET.
Special handles
Some systems allow BGET#0 to read from the character input stream via OSRDCH.
Entry points
- BBC BASIC Entry Address: &FFD7
- 6502 Entry Address: &FFD7, vectors via &0216
- Z80 Entry Address: &FFD7, vectors via &FFD8
- 6809 Entry Address: &FFD7, vectors via &FFD8
- 80x86 Entry Address: INT &43, vectors via 0000:010C
- 32000 Entry Address: SVC &0D
- PDP-11 Entry Address: EMT 9, vector &09
- ARM Entry Address: SWI &0A "OS_BGet", vector &0A
- 68000 Entry Address: MOV #&0A,A0:TRAP 12
- RISC-V Entry Address: ECALL &AC0009
Implementations
All filing systems implement OSBGET.
| Filing System Calls | |
|---|---|
Jgharston 16:56, 6 November 2009 (UTC)
