Author: jkim
Date: Thu Feb 18 23:03:37 2016
New Revision: 295776
URL: https://svnweb.freebsd.org/changeset/base/295776
Log:
Optimize ROL and ROR emulations and fix comments.
Modified:
head/sys/contrib/x86emu/x86emu.c
Modified: head/sys/contrib/x86emu/x86emu.c
==============================================================================
--- head/sys/contrib/x86emu/x86emu.c Thu Feb 18 23:00:01 2016
(r295775)
+++ head/sys/contrib/x86emu/x86emu.c Thu Feb 18 23:03:37 2016
(r295776)
@@ -6995,15 +6995,13 @@ rol_byte(struct x86emu *emu, uint8_t d,
mask = (1 << cnt) - 1;
res |= (d >> (8 - cnt)) & mask;
- /* set the new carry flag, Note that it is the low order bit
- * of the result!!! */
- CONDITIONAL_SET_FLAG(res & 0x1, F_CF);
/* OVERFLOW is set *IFF* s==1, then it is the xor of CF and
* the most significant bit. Blecck. */
CONDITIONAL_SET_FLAG(s == 1 &&
XOR2((res & 0x1) + ((res >> 6) & 0x2)),
F_OF);
- } else if (s != 0) {
+ }
+ if (s != 0) {
/* set the new carry flag, Note that it is the low order bit
* of the result!!! */
CONDITIONAL_SET_FLAG(res & 0x1, F_CF);
@@ -7025,11 +7023,11 @@ rol_word(struct x86emu *emu, uint16_t d,
res = (d << cnt);
mask = (1 << cnt) - 1;
res |= (d >> (16 - cnt)) & mask;
- CONDITIONAL_SET_FLAG(res & 0x1, F_CF);
CONDITIONAL_SET_FLAG(s == 1 &&
XOR2((res & 0x1) + ((res >> 14) & 0x2)),
F_OF);
- } else if (s != 0) {
+ }
+ if (s != 0) {
/* set the new carry flag, Note that it is the low order bit
* of the result!!! */
CONDITIONAL_SET_FLAG(res & 0x1, F_CF);
@@ -7051,11 +7049,11 @@ rol_long(struct x86emu *emu, uint32_t d,
res = (d << cnt);
mask = (1 << cnt) - 1;
res |= (d >> (32 - cnt)) & mask;
- CONDITIONAL_SET_FLAG(res & 0x1, F_CF);
CONDITIONAL_SET_FLAG(s == 1 &&
XOR2((res & 0x1) + ((res >> 30) & 0x2)),
F_OF);
- } else if (s != 0) {
+ }
+ if (s != 0) {
/* set the new carry flag, Note that it is the low order bit
* of the result!!! */
CONDITIONAL_SET_FLAG(res & 0x1, F_CF);
@@ -7093,14 +7091,12 @@ ror_byte(struct x86emu *emu, uint8_t d,
mask = (1 << (8 - cnt)) - 1;
res |= (d >> (cnt)) & mask;
- /* set the new carry flag, Note that it is the low order bit
- * of the result!!! */
- CONDITIONAL_SET_FLAG(res & 0x80, F_CF);
/* OVERFLOW is set *IFF* s==1, then it is the xor of the two
* most significant bits. Blecck. */
CONDITIONAL_SET_FLAG(s == 1 && XOR2(res >> 6), F_OF);
- } else if (s != 0) {
- /* set the new carry flag, Note that it is the low order bit
+ }
+ if (s != 0) {
+ /* set the new carry flag, Note that it is the high order bit
* of the result!!! */
CONDITIONAL_SET_FLAG(res & 0x80, F_CF);
}
@@ -7121,10 +7117,10 @@ ror_word(struct x86emu *emu, uint16_t d,
res = (d << (16 - cnt));
mask = (1 << (16 - cnt)) - 1;
res |= (d >> (cnt)) & mask;
- CONDITIONAL_SET_FLAG(res & 0x8000, F_CF);
CONDITIONAL_SET_FLAG(s == 1 && XOR2(res >> 14), F_OF);
- } else if (s != 0) {
- /* set the new carry flag, Note that it is the low order bit
+ }
+ if (s != 0) {
+ /* set the new carry flag, Note that it is the high order bit
* of the result!!! */
CONDITIONAL_SET_FLAG(res & 0x8000, F_CF);
}
@@ -7145,10 +7141,10 @@ ror_long(struct x86emu *emu, uint32_t d,
res = (d << (32 - cnt));
mask = (1 << (32 - cnt)) - 1;
res |= (d >> (cnt)) & mask;
- CONDITIONAL_SET_FLAG(res & 0x80000000, F_CF);
CONDITIONAL_SET_FLAG(s == 1 && XOR2(res >> 30), F_OF);
- } else if (s != 0) {
- /* set the new carry flag, Note that it is the low order bit
+ }
+ if (s != 0) {
+ /* set the new carry flag, Note that it is the high order bit
* of the result!!! */
CONDITIONAL_SET_FLAG(res & 0x80000000, F_CF);
}
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