projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 505bf312 KB |
1 | /*- |
| 2 | * Copyright (c) 1980 The Regents of the University of California. | |
| 3 | * All rights reserved. | |
| 4 | * | |
| 5 | * %sccs.include.redist.c% | |
| f644bb55 | 6 | */ |
| 18e2a93b | 7 | |
| f644bb55 | 8 | #ifndef lint |
| 505bf312 KB |
9 | static char sccsid[] = "@(#)entry.c 5.2 (Berkeley) %G%"; |
| 10 | #endif /* not lint */ | |
| 11 | ||
| 18e2a93b ML |
12 | /* |
| 13 | * routines to deal with the entry addresses of blocks | |
| 14 | */ | |
| 15 | ||
| 16 | #include "defs.h" | |
| 17 | #include "runtime.h" | |
| 18 | #include "frame.rep" | |
| 19 | #include "machine.h" | |
| 20 | #include "process.h" | |
| 21 | #include "sym.h" | |
| 22 | #include "source.h" | |
| 23 | #include "object.h" | |
| 24 | #include "process/pxinfo.h" | |
| 25 | #include "process/process.rep" | |
| 26 | ||
| 27 | /* | |
| 28 | * Return the address of the beginning of the procedure/function | |
| 29 | * associated with the given frame. | |
| 30 | */ | |
| 31 | ||
| 32 | ADDRESS entry(frp) | |
| 33 | register FRAME *frp; | |
| 34 | { | |
| 35 | return(frp->blockp - 2 - ENDOFF); | |
| 36 | } | |
| 37 | ||
| 38 | /* | |
| 39 | * Find the entry address of the caller of the current block. | |
| 40 | * This is only called in connection with breakpoints. | |
| 41 | * | |
| 42 | * This routine assumes it is at the very beginning of the block. | |
| 43 | */ | |
| 44 | ||
| 45 | ADDRESS caller_addr() | |
| 46 | { | |
| 47 | FRAME *frp; | |
| 48 | ||
| 49 | if ((frp = curframe()) == NIL) { | |
| 50 | panic("caller_addr(main program)"); | |
| 51 | } | |
| 52 | frp = nextframe(frp); | |
| 53 | if (frp == NIL) { | |
| 54 | return(codeloc(program)); | |
| 55 | } else { | |
| 56 | return(entry(frp)); | |
| 57 | } | |
| 58 | } | |
| 59 | ||
| 60 | /* | |
| 61 | * Find the return address of the current procedure/function. | |
| 62 | * | |
| 63 | * There are two special cases: | |
| 64 | * | |
| 65 | * we're right at the beginning of the main program | |
| 66 | * we're right at the beginning of some procedure or function | |
| 67 | * | |
| 68 | * The first one is handled by returning the last instruction in | |
| 69 | * the object code. In the second case, we get the return address | |
| 70 | * directly from the process' stack. | |
| 71 | */ | |
| 72 | ||
| 73 | ADDRESS return_addr() | |
| 74 | { | |
| 75 | ADDRESS addr; | |
| 76 | FRAME *frp, frame; | |
| 77 | ||
| 78 | if (pc == codeloc(program)) { | |
| 79 | addr = lastaddr(); | |
| 80 | } else { | |
| 81 | frp = curframe(); | |
| 82 | if (frp == NIL) { | |
| 83 | dread(&frame, (ADDRESS) process->sp, sizeof(FRAME)); | |
| 84 | addr = frame.save_pc - ENDOFF; | |
| 85 | } else { | |
| 86 | addr = frp->save_pc; | |
| 87 | } | |
| 88 | } | |
| 89 | return addr; | |
| 90 | } | |
| 91 | ||
| 92 | /* | |
| 93 | * Calculate the entry address for a procedure or function parameter, | |
| 94 | * given the address of the descriptor. | |
| 95 | */ | |
| 96 | ||
| 97 | ADDRESS fparamaddr(a) | |
| 98 | ADDRESS a; | |
| 99 | { | |
| 100 | ADDRESS r; | |
| 101 | ||
| 102 | dread(&r, a, sizeof(r)); | |
| 103 | return (r - ENDOFF); | |
| 104 | } |