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Add SGI-compatible ta0-ta3 register names. These allow one to write

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asm code which can be built easily in old-ABI and new-ABI environemnts.

In old-ABI, they map to t4-t7, and in new-ABI, they map to a4-a7.  This
means that t0-t3,ta0-ta3,t8,t9 are available in both ABIs.

Because ta0-ta3 overlap with arg regs (albeit arg slots which are usually
unused), they should be used only if t0-t3,t8,t9 isn't enough.
This commit is contained in:
thorpej 2002-11-04 03:38:32 +00:00
parent bae541911c
commit aa2b9a65fc
1 changed files with 21 additions and 1 deletions
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22
sys/arch/mips/include/regdef.h
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@ -1,4 +1,4 @@
/* $NetBSD: regdef.h,v 1.9 2002/11/02 02:00:17 thorpej Exp $ */
/* $NetBSD: regdef.h,v 1.10 2002/11/04 03:38:32 thorpej Exp $ */
/*
* Copyright (c) 1992, 1993
@ -88,4 +88,24 @@
#define s8 $30 /* one more callee saved */
#define ra $31 /* return address */
/*
* These are temp registers whose names can be used in either the old
* or new ABI, although they map to different physical registers. In
* the old ABI, they map to t4-t7, and in the new ABI, they map to a4-a7.
*
* Because they overlap with the last 4 arg regs in the new ABI, ta0-ta3
* should be used only when we need more than t0-t3.
*/
#if defined(__mips_n32) || defined(__mips_n64)
#define ta0 $8
#define ta1 $9
#define ta2 $10
#define ta3 $11
#else
#define ta0 $12
#define ta1 $13
#define ta2 $14
#define ta3 $15
#endif /* __mips_n32 || __mips_n64 */
#endif /* _MIPS_REGDEF_H */