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authorTaru Karttunen <taruti@taruti.net>2011-03-30 15:46:40 +0300
committerTaru Karttunen <taruti@taruti.net>2011-03-30 15:46:40 +0300
commite5888a1ffdae813d7575f5fb02275c6bb07e5199 (patch)
treed8d51eac403f07814b9e936eed0c9a79195e2450 /sys/src/libc/arm/memmove.s
Import sources from 2011-03-30 iso image
Diffstat (limited to 'sys/src/libc/arm/memmove.s')
-rwxr-xr-xsys/src/libc/arm/memmove.s212
1 files changed, 212 insertions, 0 deletions
diff --git a/sys/src/libc/arm/memmove.s b/sys/src/libc/arm/memmove.s
new file mode 100755
index 000000000..346a23d72
--- /dev/null
+++ b/sys/src/libc/arm/memmove.s
@@ -0,0 +1,212 @@
+TS = 0
+TE = 1
+FROM = 2
+N = 3
+TMP = 3 /* N and TMP don't overlap */
+TMP1 = 4
+
+TEXT memcpy(SB), $-4
+ B _memmove
+TEXT memmove(SB), $-4
+_memmove:
+ MOVW R(TS), to+0(FP) /* need to save for return value */
+ MOVW from+4(FP), R(FROM)
+ MOVW n+8(FP), R(N)
+
+ ADD R(N), R(TS), R(TE) /* to end pointer */
+
+ CMP R(FROM), R(TS)
+ BLS _forward
+
+_back:
+ ADD R(N), R(FROM) /* from end pointer */
+ CMP $4, R(N) /* need at least 4 bytes to copy */
+ BLT _b1tail
+
+_b4align: /* align destination on 4 */
+ AND.S $3, R(TE), R(TMP)
+ BEQ _b4aligned
+
+ MOVBU.W -1(R(FROM)), R(TMP) /* pre-indexed */
+ MOVBU.W R(TMP), -1(R(TE)) /* pre-indexed */
+ B _b4align
+
+_b4aligned: /* is source now aligned? */
+ AND.S $3, R(FROM), R(TMP)
+ BNE _bunaligned
+
+ ADD $31, R(TS), R(TMP) /* do 32-byte chunks if possible */
+_b32loop:
+ CMP R(TMP), R(TE)
+ BLS _b4tail
+
+ MOVM.DB.W (R(FROM)), [R4-R7]
+ MOVM.DB.W [R4-R7], (R(TE))
+ MOVM.DB.W (R(FROM)), [R4-R7]
+ MOVM.DB.W [R4-R7], (R(TE))
+ B _b32loop
+
+_b4tail: /* do remaining words if possible */
+ ADD $3, R(TS), R(TMP)
+_b4loop:
+ CMP R(TMP), R(TE)
+ BLS _b1tail
+
+ MOVW.W -4(R(FROM)), R(TMP1) /* pre-indexed */
+ MOVW.W R(TMP1), -4(R(TE)) /* pre-indexed */
+ B _b4loop
+
+_b1tail: /* remaining bytes */
+ CMP R(TE), R(TS)
+ BEQ _return
+
+ MOVBU.W -1(R(FROM)), R(TMP) /* pre-indexed */
+ MOVBU.W R(TMP), -1(R(TE)) /* pre-indexed */
+ B _b1tail
+
+_forward:
+ CMP $4, R(N) /* need at least 4 bytes to copy */
+ BLT _f1tail
+
+_f4align: /* align destination on 4 */
+ AND.S $3, R(TS), R(TMP)
+ BEQ _f4aligned
+
+ MOVBU.P 1(R(FROM)), R(TMP) /* implicit write back */
+ MOVBU.P R(TMP), 1(R(TS)) /* implicit write back */
+ B _f4align
+
+_f4aligned: /* is source now aligned? */
+ AND.S $3, R(FROM), R(TMP)
+ BNE _funaligned
+
+ SUB $31, R(TE), R(TMP) /* do 32-byte chunks if possible */
+_f32loop:
+ CMP R(TMP), R(TS)
+ BHS _f4tail
+
+ MOVM.IA.W (R(FROM)), [R4-R7]
+ MOVM.IA.W [R4-R7], (R(TS))
+ MOVM.IA.W (R(FROM)), [R4-R7]
+ MOVM.IA.W [R4-R7], (R(TS))
+ B _f32loop
+
+_f4tail:
+ SUB $3, R(TE), R(TMP) /* do remaining words if possible */
+_f4loop:
+ CMP R(TMP), R(TS)
+ BHS _f1tail
+
+ MOVW.P 4(R(FROM)), R(TMP1) /* implicit write back */
+ MOVW.P R4, 4(R(TS)) /* implicit write back */
+ B _f4loop
+
+_f1tail:
+ CMP R(TS), R(TE)
+ BEQ _return
+
+ MOVBU.P 1(R(FROM)), R(TMP) /* implicit write back */
+ MOVBU.P R(TMP), 1(R(TS)) /* implicit write back */
+ B _f1tail
+
+_return:
+ MOVW to+0(FP), R0
+ RET
+
+RSHIFT = 4
+LSHIFT = 5
+OFFSET = 11
+
+BR0 = 6
+BW0 = 7
+BR1 = 7
+BW1 = 8
+
+_bunaligned:
+ CMP $2, R(TMP) /* is R(TMP) < 2 ? */
+
+ MOVW.LT $8, R(RSHIFT) /* (R(n)<<24)|(R(n-1)>>8) */
+ MOVW.LT $24, R(LSHIFT)
+ MOVW.LT $1, R(OFFSET)
+
+ MOVW.EQ $16, R(RSHIFT) /* (R(n)<<16)|(R(n-1)>>16) */
+ MOVW.EQ $16, R(LSHIFT)
+ MOVW.EQ $2, R(OFFSET)
+
+ MOVW.GT $24, R(RSHIFT) /* (R(n)<<8)|(R(n-1)>>24) */
+ MOVW.GT $8, R(LSHIFT)
+ MOVW.GT $3, R(OFFSET)
+
+ ADD $8, R(TS), R(TMP) /* do 8-byte chunks if possible */
+ CMP R(TMP), R(TE)
+ BLS _b1tail
+
+ BIC $3, R(FROM) /* align source */
+ MOVW (R(FROM)), R(BR0) /* prime first block register */
+
+_bu8loop:
+ CMP R(TMP), R(TE)
+ BLS _bu1tail
+
+ MOVW R(BR0)<<R(LSHIFT), R(BW1)
+ MOVM.DB.W (R(FROM)), [R(BR0)-R(BR1)]
+ ORR R(BR1)>>R(RSHIFT), R(BW1)
+
+ MOVW R(BR1)<<R(LSHIFT), R(BW0)
+ ORR R(BR0)>>R(RSHIFT), R(BW0)
+
+ MOVM.DB.W [R(BW0)-R(BW1)], (R(TE))
+ B _bu8loop
+
+_bu1tail:
+ ADD R(OFFSET), R(FROM)
+ B _b1tail
+
+RSHIFT = 4
+LSHIFT = 5
+OFFSET = 11
+
+FW0 = 6
+FR0 = 7
+FW1 = 7
+FR1 = 8
+
+_funaligned:
+ CMP $2, R(TMP)
+
+ MOVW.LT $8, R(RSHIFT) /* (R(n+1)<<24)|(R(n)>>8) */
+ MOVW.LT $24, R(LSHIFT)
+ MOVW.LT $3, R(OFFSET)
+
+ MOVW.EQ $16, R(RSHIFT) /* (R(n+1)<<16)|(R(n)>>16) */
+ MOVW.EQ $16, R(LSHIFT)
+ MOVW.EQ $2, R(OFFSET)
+
+ MOVW.GT $24, R(RSHIFT) /* (R(n+1)<<8)|(R(n)>>24) */
+ MOVW.GT $8, R(LSHIFT)
+ MOVW.GT $1, R(OFFSET)
+
+ SUB $8, R(TE), R(TMP) /* do 8-byte chunks if possible */
+ CMP R(TMP), R(TS)
+ BHS _f1tail
+
+ BIC $3, R(FROM) /* align source */
+ MOVW.P 4(R(FROM)), R(FR1) /* prime last block register, implicit write back */
+
+_fu8loop:
+ CMP R(TMP), R(TS)
+ BHS _fu1tail
+
+ MOVW R(FR1)>>R(RSHIFT), R(FW0)
+ MOVM.IA.W (R(FROM)), [R(FR0)-R(FR1)]
+ ORR R(FR0)<<R(LSHIFT), R(FW0)
+
+ MOVW R(FR0)>>R(RSHIFT), R(FW1)
+ ORR R(FR1)<<R(LSHIFT), R(FW1)
+
+ MOVM.IA.W [R(FW0)-R(FW1)], (R(TS))
+ B _fu8loop
+
+_fu1tail:
+ SUB R(OFFSET), R(FROM)
+ B _f1tail