Change x86 syscalls to direct branches, and define abi for additional syscalls.

[polintos/scott/priv.git] / doc / abi / x86

diff --git a/doc/abi/x86 b/doc/abi/x86
index 41f4bb43269ae23594c0a335bb9cb0d5d25be089..7a11bd11a47a813b1a6962e25d1953da52ff9563 100644 (file)
--- a/doc/abi/x86
+++ b/doc/abi/x86
@@ -2,33 +2,38 @@ Basic ABI: SysV i386
 
 Out-of-Process Method Invocation:
    Caller:
-      eax: reserved, must be zero
-      edx: pointer to parameter info block (PIB)
-      ecx: maximum "out" bytes, excluding Inlines
+      eax: pointer to parameter info block (PIB)
 
-      Call the 32-bit address stored at 0x7fff0000 to invoke the method.
+      Call 0x7fff0000 to invoke the method.
       
       Upon return:
       ebx, esi, edi, ebp, esp: preserved
-      eax: pointer to exception, or NULL if none.
+      eax: pointer to exception, or NULL if none
            If there is an exception, the user part of the syscall
            function will search for an exception handling function
            that covers the calling address.  If none is found,
            it will assume that it is a language without exception
-           handling, and return the exception to the caller in eax.
-      ecx: clobbered
-      edx: pointer to args, with out params filled in; in params
-           may be clobbered.  This will be the same pointer as
-           was passed in by the caller.
+           handling, an5Ad return the exception to the caller in eax.
+      edx: length of exception segment, if any
+      ecx: may be clobbered
       
    Callee:
       eax: pointer to PIB
-      edx: pointer to caller information struct, if such was
+      edx: pointer to caller information struct, or NULL if not
            requested
-      ecx: return address
+      esp: NULL.
+
+      Jump to 0x7fff0080 to return.
       
       Upon return:
-      
-      eax: pointer to exception, or NULL if none.
-      ebx, esi, edi, ebp, esp: should be preserved
-      ecx, edx: may be clobbered
+      eax: pointer to exception, or NULL if none
+      edx: length of exception segment, if any
+      ebx, ecx, esi, edi, ebp, esp: may be clobbered
+
+Other system calls:
+       eax, edx, ecx: syscall arguments.
+       
+       Call 0x7fff0000 + 0x80 * syscallnum
+
+       eax: return value
+       edx, ecx: may be clobbered