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authorZong Li <zong@andestech.com>2018-11-01 17:34:39 +0000
committerJoseph Myers <joseph@codesourcery.com>2018-11-01 17:34:39 +0000
commitff48ea6787526d7e669af93ce2681b911d39675c (patch)
treee62f4b7c05f630df014ad5a2524535b990a804c1 /soft-fp
parenteac4405af00464a4268cfd13b25224901c193988 (diff)
downloadglibc-ff48ea6787526d7e669af93ce2681b911d39675c.tar.gz
soft-fp: Use temporary variable in FP_FRAC_SUB_3/FP_FRAC_SUB_4
In FRAC_SUB_3(R, X, Y) and FRAC_SUB_4(R,, X, Y), it reference both the X[N] and X[N] after R[N] have been set. If one of the X and Y is the same address with R, the result of the calculation is wrong, because the value of the original X and Y are overwritten. In glibc, there are two places use FRAC_SUB and occurs the overlap. The first is _FP_DIV_MEAT_N_loop in op-common.h, it uses the source _FP_DIV_MEAT_N_loop_u as the destination. This macro only be used when N is one(_FP_DIV_MEAT_1_loop) and then the _FP_FRAC_SUB_##wc extend to _FP_FRAC_SUB_1 in this macro. so it also work because _FP_FRAC_SUB_1 has no overlap problem in its implementation. The second places is _FP_DIV_MEAT_4_udiv, the original value of X##_f[0] is overwritten before the calculatation. In FRAC_SUB_1 and FRAC_SUB_2, there don't refer the source after destination have been set, so they have no problem. After this modification, we can pass the soft floating testing of glibc testsuites on RV32. * soft-fp/op-4.h (_FP_FRAC_SUB_3, _FP_FRAC_SUB_4): Use temporary variable to avoid overlap arguments.
Diffstat (limited to 'soft-fp')
-rw-r--r--soft-fp/op-4.h63
1 files changed, 35 insertions, 28 deletions
diff --git a/soft-fp/op-4.h b/soft-fp/op-4.h
index 01b87d01a1..b429801687 100644
--- a/soft-fp/op-4.h
+++ b/soft-fp/op-4.h
@@ -696,39 +696,46 @@
#endif
#ifndef __FP_FRAC_SUB_3
-# define __FP_FRAC_SUB_3(r2, r1, r0, x2, x1, x0, y2, y1, y0) \
- do \
- { \
- _FP_W_TYPE __FP_FRAC_SUB_3_c1, __FP_FRAC_SUB_3_c2; \
- r0 = x0 - y0; \
- __FP_FRAC_SUB_3_c1 = r0 > x0; \
- r1 = x1 - y1; \
- __FP_FRAC_SUB_3_c2 = r1 > x1; \
- r1 -= __FP_FRAC_SUB_3_c1; \
- __FP_FRAC_SUB_3_c2 |= __FP_FRAC_SUB_3_c1 && (y1 == x1); \
- r2 = x2 - y2 - __FP_FRAC_SUB_3_c2; \
- } \
+# define __FP_FRAC_SUB_3(r2, r1, r0, x2, x1, x0, y2, y1, y0) \
+ do \
+ { \
+ _FP_W_TYPE __FP_FRAC_SUB_3_tmp[2]; \
+ _FP_W_TYPE __FP_FRAC_SUB_3_c1, __FP_FRAC_SUB_3_c2; \
+ __FP_FRAC_SUB_3_tmp[0] = x0 - y0; \
+ __FP_FRAC_SUB_3_c1 = __FP_FRAC_SUB_3_tmp[0] > x0; \
+ __FP_FRAC_SUB_3_tmp[1] = x1 - y1; \
+ __FP_FRAC_SUB_3_c2 = __FP_FRAC_SUB_3_tmp[1] > x1; \
+ __FP_FRAC_SUB_3_tmp[1] -= __FP_FRAC_SUB_3_c1; \
+ __FP_FRAC_SUB_3_c2 |= __FP_FRAC_SUB_3_c1 && (y1 == x1); \
+ r2 = x2 - y2 - __FP_FRAC_SUB_3_c2; \
+ r1 = __FP_FRAC_SUB_3_tmp[1]; \
+ r0 = __FP_FRAC_SUB_3_tmp[0]; \
+ } \
while (0)
#endif
#ifndef __FP_FRAC_SUB_4
# define __FP_FRAC_SUB_4(r3, r2, r1, r0, x3, x2, x1, x0, y3, y2, y1, y0) \
- do \
- { \
- _FP_W_TYPE __FP_FRAC_SUB_4_c1, __FP_FRAC_SUB_4_c2; \
- _FP_W_TYPE __FP_FRAC_SUB_4_c3; \
- r0 = x0 - y0; \
- __FP_FRAC_SUB_4_c1 = r0 > x0; \
- r1 = x1 - y1; \
- __FP_FRAC_SUB_4_c2 = r1 > x1; \
- r1 -= __FP_FRAC_SUB_4_c1; \
- __FP_FRAC_SUB_4_c2 |= __FP_FRAC_SUB_4_c1 && (y1 == x1); \
- r2 = x2 - y2; \
- __FP_FRAC_SUB_4_c3 = r2 > x2; \
- r2 -= __FP_FRAC_SUB_4_c2; \
- __FP_FRAC_SUB_4_c3 |= __FP_FRAC_SUB_4_c2 && (y2 == x2); \
- r3 = x3 - y3 - __FP_FRAC_SUB_4_c3; \
- } \
+ do \
+ { \
+ _FP_W_TYPE __FP_FRAC_SUB_4_tmp[3]; \
+ _FP_W_TYPE __FP_FRAC_SUB_4_c1, __FP_FRAC_SUB_4_c2; \
+ _FP_W_TYPE __FP_FRAC_SUB_4_c3; \
+ __FP_FRAC_SUB_4_tmp[0] = x0 - y0; \
+ __FP_FRAC_SUB_4_c1 = __FP_FRAC_SUB_4_tmp[0] > x0; \
+ __FP_FRAC_SUB_4_tmp[1] = x1 - y1; \
+ __FP_FRAC_SUB_4_c2 = __FP_FRAC_SUB_4_tmp[1] > x1; \
+ __FP_FRAC_SUB_4_tmp[1] -= __FP_FRAC_SUB_4_c1; \
+ __FP_FRAC_SUB_4_c2 |= __FP_FRAC_SUB_4_c1 && (y1 == x1); \
+ __FP_FRAC_SUB_4_tmp[2] = x2 - y2; \
+ __FP_FRAC_SUB_4_c3 = __FP_FRAC_SUB_4_tmp[2] > x2; \
+ __FP_FRAC_SUB_4_tmp[2] -= __FP_FRAC_SUB_4_c2; \
+ __FP_FRAC_SUB_4_c3 |= __FP_FRAC_SUB_4_c2 && (y2 == x2); \
+ r3 = x3 - y3 - __FP_FRAC_SUB_4_c3; \
+ r2 = __FP_FRAC_SUB_4_tmp[2]; \
+ r1 = __FP_FRAC_SUB_4_tmp[1]; \
+ r0 = __FP_FRAC_SUB_4_tmp[0]; \
+ } \
while (0)
#endif