big: implemented core shift routines in arith.go and

     provide assembly versions (for x86-64 for now)

(Not yet used - waiting for previous CL to clear)

R=rsc
CC=golang-dev
https://golang.org/cl/1040041

diff --git a/src/pkg/big/arith.go b/src/pkg/big/arith.go
index 4f18ed37b32dc61faef863f1a08b0267bacafba8..1c481caabc65e4df3fde3436ea51fcfda19e4d0d 100644 (file)
--- a/src/pkg/big/arith.go
+++ b/src/pkg/big/arith.go
@@ -310,6 +310,28 @@ func subVW_g(z, x *Word, y Word, n int) (c Word) {
 }
 
 
+func shlVW(z, x *Word, s Word, n int) (c Word)
+func shlVW_g(z, x *Word, s Word, n int) (c Word) {
+       ŝ := _W - s
+       for i := 0; i < n; i++ {
+               w := *x.at(i)
+               c, *z.at(i) = w>>ŝ, w<<s|c
+       }
+       return
+}
+
+
+func shrVW(z, x *Word, s Word, n int) (c Word)
+func shrVW_g(z, x *Word, s Word, n int) (c Word) {
+       ŝ := _W - s
+       for i := n - 1; i >= 0; i-- {
+               w := *x.at(i)
+               c, *z.at(i) = w<<ŝ, w>>s|c
+       }
+       return
+}
+
+
 func mulAddVWW(z, x *Word, y, r Word, n int) (c Word)
 func mulAddVWW_g(z, x *Word, y, r Word, n int) (c Word) {
        c = r

diff --git a/src/pkg/big/arith_386.s b/src/pkg/big/arith_386.s
index 75fcd7c20022d91d3fcdfa9e59ff05ee4cd1f256..83398db944a304c3345a52b8fff84e87f6dc379a 100644 (file)
--- a/src/pkg/big/arith_386.s
+++ b/src/pkg/big/arith_386.s
@@ -99,6 +99,20 @@ E4:  CMPL BX, BP         // i < n
        RET
 
 
+// func shlVW(z, x *Word, s Word, n int) (c Word)
+// TODO(gri) implement this routine
+TEXT ·shlVW(SB),7,$0
+       NOP                     // work around bug in linker
+       JMP ·shlVW_g(SB)
+
+
+// func shrVW(z, x *Word, s Word, n int) (c Word)
+// TODO(gri) implement this routine
+TEXT ·shrVW(SB),7,$0
+       NOP                     // work around bug in linker
+       JMP ·shrVW_g(SB)
+
+
 // func mulAddVWW(z, x *Word, y, r Word, n int) (c Word)
 TEXT ·mulAddVWW(SB),7,$0
        MOVL z+0(FP), DI

diff --git a/src/pkg/big/arith_amd64.s b/src/pkg/big/arith_amd64.s
index da53b76a8bdc806af125f21f6d6612d3df23b92e..5f9b4782da36e1e327db39ba5fd47c63d63941d9 100644 (file)
--- a/src/pkg/big/arith_amd64.s
+++ b/src/pkg/big/arith_amd64.s
@@ -101,6 +101,56 @@ E4:        CMPQ BX, R11         // i < n
        RET
 
 
+// func shlVW(z, x *Word, s Word, n int) (c Word)
+TEXT ·shlVW(SB),7,$0
+       MOVQ z+0(FP), R10
+       MOVQ x+8(FP), R8
+       MOVQ s+16(FP), CX
+       MOVL n+24(FP), R11
+       MOVQ $0, AX         // c = 0
+       MOVQ $0, BX         // i = 0
+       JMP E8
+
+L8:    MOVQ (R8)(BX*8), DX
+       MOVQ DX, R12
+       SHLQ CX, DX:AX
+       MOVQ DX, (R10)(BX*8)
+       MOVQ R12, AX
+       ADDL $1, BX          // i++
+
+E8:    CMPQ BX, R11         // i < n
+       JL L8
+
+       MOVQ $0, DX
+       SHLQ CX, DX:AX
+       MOVQ DX, c+32(FP)
+       RET
+
+
+// func shrVW(z, x *Word, s Word, n int) (c Word)
+TEXT ·shrVW(SB),7,$0
+       MOVQ z+0(FP), R10
+       MOVQ x+8(FP), R8
+       MOVQ s+16(FP), CX
+       MOVL n+24(FP), BX   // i = n
+       MOVQ $0, AX         // c = 0
+       JMP E9
+
+L9:    MOVQ (R8)(BX*8), DX
+       MOVQ DX, R12
+       SHRQ CX, DX:AX
+       MOVQ DX, (R10)(BX*8)
+       MOVQ R12, AX
+
+E9:    SUBL $1, BX         // i--
+       JGE L9
+
+       MOVQ $0, DX
+       SHRQ CX, DX:AX
+       MOVQ DX, c+32(FP)
+       RET
+
+
 // func mulAddVWW(z, x *Word, y, r Word, n int) (c Word)
 TEXT ·mulAddVWW(SB),7,$0
        MOVQ z+0(FP), R10

diff --git a/src/pkg/big/arith_arm.s b/src/pkg/big/arith_arm.s
index 0e78a82f64224d33abf9ed356023b9e592add399..c8a45efc491ab6c3ee6871991857f9422a74bdd7 100644 (file)
--- a/src/pkg/big/arith_arm.s
+++ b/src/pkg/big/arith_arm.s
@@ -18,6 +18,12 @@ TEXT ·addVW(SB),7,$0
 TEXT ·subVW(SB),7,$0
        B ·subVW_g(SB)
 
+TEXT ·shlVW(SB),7,$0
+       B ·shlVW_g(SB)
+
+TEXT ·shrVW(SB),7,$0
+       B ·shrVW_g(SB)
+
 TEXT ·mulAddVWW(SB),7,$0
        B ·mulAddVWW_g(SB)
 

diff --git a/src/pkg/big/arith_test.go b/src/pkg/big/arith_test.go
index 49908e342de347022a5fe16ebc34c4978b337399..6ee1459c689929336eba5f5053321cfd302e38e5 100644 (file)
--- a/src/pkg/big/arith_test.go
+++ b/src/pkg/big/arith_test.go
@@ -147,6 +147,36 @@ var prodVW = []argVW{
        argVW{nat{_M << 7 & _M, _M, _M, _M}, nat{_M, _M, _M, _M}, 1 << 7, _M >> (_W - 7)},
 }
 
+var lshVW = []argVW{
+       argVW{},
+       argVW{nat{0}, nat{0}, 0, 0},
+       argVW{nat{0}, nat{0}, 1, 0},
+       argVW{nat{0}, nat{0}, 20, 0},
+
+       argVW{nat{_M}, nat{_M}, 0, 0},
+       argVW{nat{_M << 1 & _M}, nat{_M}, 1, 1},
+       argVW{nat{_M << 20 & _M}, nat{_M}, 20, _M >> (_W - 20)},
+
+       argVW{nat{_M, _M, _M}, nat{_M, _M, _M}, 0, 0},
+       argVW{nat{_M << 1 & _M, _M, _M}, nat{_M, _M, _M}, 1, 1},
+       argVW{nat{_M << 20 & _M, _M, _M}, nat{_M, _M, _M}, 20, _M >> (_W - 20)},
+}
+
+var rshVW = []argVW{
+       argVW{},
+       argVW{nat{0}, nat{0}, 0, 0},
+       argVW{nat{0}, nat{0}, 1, 0},
+       argVW{nat{0}, nat{0}, 20, 0},
+
+       argVW{nat{_M}, nat{_M}, 0, 0},
+       argVW{nat{_M >> 1}, nat{_M}, 1, _M << (_W - 1) & _M},
+       argVW{nat{_M >> 20}, nat{_M}, 20, _M << (_W - 20) & _M},
+
+       argVW{nat{_M, _M, _M}, nat{_M, _M, _M}, 0, 0},
+       argVW{nat{_M, _M, _M >> 1}, nat{_M, _M, _M}, 1, _M << (_W - 1) & _M},
+       argVW{nat{_M, _M, _M >> 20}, nat{_M, _M, _M}, 20, _M << (_W - 20) & _M},
+}
+
 
 func testFunVW(t *testing.T, msg string, f funVW, a argVW) {
        n := len(a.z)
@@ -174,6 +204,18 @@ func TestFunVW(t *testing.T) {
                testFunVW(t, "subVW_g", subVW_g, arg)
                testFunVW(t, "subVW", subVW, arg)
        }
+
+       for _, a := range lshVW {
+               arg := a
+               testFunVW(t, "shlVW_g", shlVW_g, arg)
+               testFunVW(t, "shlVW", shlVW, arg)
+       }
+
+       for _, a := range rshVW {
+               arg := a
+               testFunVW(t, "shrVW_g", shrVW_g, arg)
+               testFunVW(t, "shrVW", shrVW, arg)
+       }
 }