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pdp10-abi.txt: update definition of register contents at process start

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Mikael Pettersson 2023-08-22 19:34:34 +02:00
parent 9239504ce1
commit 5754587b35
1 changed files with 6 additions and 2 deletions
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doc/pdp10-abi.txt
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@ -770,6 +770,8 @@ SP: | Argument count word | High Address
| information (size varies) | Low Address
+----------------------------------------+
[TODO: The above stack layout is subject to change, the below register contents is correct.]
When a process is first entered (from an exec() system call), the contents of registers
other than those listed below are unspecified. Consequently, a program that requires
registers to have specific values must set them explicitly during process initialization.
@ -778,8 +780,10 @@ registers whose contents are specified:
Figure 3-??
017 The initial stack pointer, pointing to a stack location that contains the
argument count.
001 Argument count (argc).
002 Pointer to NULL-terminated array of pointers to argument strings (argv).
003 Pointer to NULL-terminated array of pointers to environment strings (envp).
017 The initial stack pointer.
[TODO: a register e.g. 1 with a function pointer for atexit()?
Not all archs use that. Only if Linux really wants it.]