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csu: Avoid additional nops in the MIPS INIT_CALL_SEQ macro

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Since we had a .set reorder, the nop after the "jal" was being placed after
the delay slot, resulting in two nops.
While changing this code also guard the .set noreorder with .set push/pop
and use $zero as the cpsetup save register since we don't need to save $gp.

Reviewed By:	jhb
Differential Revision: https://reviews.freebsd.org/D25025
This commit is contained in:
arichardson 2020-06-05 08:46:55 +00:00
parent 58e4141680
commit 69c93432ca
1 changed files with 7 additions and 5 deletions
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12
lib/csu/mips/crt.h
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@ -30,29 +30,31 @@
#define CTORS_CONSTRUCTORS
#ifdef __mips_o32
#define INIT_CALL_SEQ(func) \
".set push \n" \
".set noreorder \n" \
"bal 1f \n" \
"nop \n" \
"1: \n" \
".cpload $ra \n" \
"addu $sp, $sp, -8 \n" \
".set reorder \n" \
".cprestore 4 \n" \
".local " __STRING(func) "\n" \
"jal " __STRING(func) "\n" \
"nop \n" \
"addu $sp, $sp, 8 \n"
"addu $sp, $sp, 8 \n" \
".set pop\n"
#else
#define INIT_CALL_SEQ(func) \
".set push \n" \
".set noreorder \n" \
"bal 1f \n" \
"nop \n" \
"1: \n" \
".set reorder \n" \
".cpsetup $ra, $v0, 1b \n" \
".cpsetup $ra, $zero, 1b \n" \
".local " __STRING(func) "\n" \
"jal " __STRING(func) "\n" \
"nop \n"
"nop \n" \
".set pop\n"
#endif
#endif