From: Guillermo J. Rozas Date: Wed, 22 Jan 1992 04:19:13 +0000 (+0000) Subject: Fix comment with register allocation. X-Git-Tag: 20090517-FFI~9950 X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=ddf138b6fdb993aa446a5469c1faf16d6e849436;p=mit-scheme.git Fix comment with register allocation. EBX is now free, the value register is contained in memory. --- diff --git a/v7/src/microcode/cmpintmd/i386.h b/v7/src/microcode/cmpintmd/i386.h index 2fd7a4df5..e7ebc0705 100644 --- a/v7/src/microcode/cmpintmd/i386.h +++ b/v7/src/microcode/cmpintmd/i386.h @@ -1,6 +1,6 @@ /* -*-C-*- -$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/cmpintmd/i386.h,v 1.1 1992/01/21 00:08:14 jinx Exp $ +$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/cmpintmd/i386.h,v 1.2 1992/01/22 04:19:13 jinx Exp $ Copyright (c) 1992 Massachusetts Institute of Technology @@ -106,24 +106,22 @@ This is one byte longer than otherwise, but... EAX (0) Unassigned ECX (1) Unassigned EDX (2) Unassigned -EBX (3) Value register +EBX (3) Unassigned ESP (4) Stack Pointer EBP (5) Register Mask ESI (6) Pointer to register block, etc. EDI (7) Free Pointer -The dynamic link is not stored in a processor register. A slot in the -register array must be reserved for it. - -Note: Perhaps the value register should also be stored in the register -array. +The dynamic link and value "registers" are not processor registers. +Slots in the register array must be reserved for them. The Free Pointer is EDI because EDI is the implicit base register for the memory-to-memory move instructions, and the string store instruction. Perhaps we can make use of it. -The register mask is not in EBP, its natural register, because (EBP) +The pointer to register block is not held in EBP (the processor's +"frame" register is typically used) because its most common use, (EBP) (address syllable for memory memtop) takes more bytes than (ESI). Encodings and layout of various control features: