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cmd/internal/obj/riscv: implement AUIPC and LUI instructions 

Add support for assembling AUIPC and LUI instructions.

Based on the riscv-go port.

Updates #27532

Change-Id: I178868b6dcc6fdc6b8527454569a3538ed50723e
Reviewed-on: https://go-review.googlesource.com/c/go/+/196840
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Joel Sing 2019-09-19 02:34:06 +10:00
parent 05c8d8d365
commit 430d2aa349
2 changed files with 77 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
src/cmd/asm/internal/asm/testdata/riscvenc.s vendored
View File

@ -57,6 +57,15 @@ TEXT asmtest(SB),DUPOK|NOSPLIT,$0
XOR $1, X5, X6 // 13c31200
XOR $1, X5 // 93c21200
AUIPC $0, X10 // 17050000
AUIPC $0, X11 // 97050000
AUIPC $1, X10 // 17150000
AUIPC $1048575, X10 // 17f5ffff
LUI $0, X15 // b7070000
LUI $167, X15 // b7770a00
LUI $1048575, X15 // b7f7ffff
SLL X6, X5, X7 // b3936200
SLL X5, X6 // 33135300
SLL $1, X5, X6 // 13931200

84
src/cmd/internal/obj/riscv/obj.go
View File

@ -192,33 +192,61 @@ func regFAddr(a obj.Addr) uint32 {
return regAddr(a, REG_F0, REG_F31)
}
// immFits reports whether immediate value x fits in nbits bits as a
// signed integer.
func immFits(x int64, nbits uint) bool {
// immIFits reports whether immediate value x fits in nbits bits
// as a signed integer.
func immIFits(x int64, nbits uint) bool {
nbits--
var min int64 = -1 << nbits
var max int64 = 1<<nbits - 1
return min <= x && x <= max
}
// immI extracts the integer literal of the specified size from an Addr.
// immUFits reports whether immediate value x fits in nbits bits
// as an unsigned integer.
func immUFits(x int64, nbits uint) bool {
var max int64 = 1<<nbits - 1
return 0 <= x && x <= max
}
// immI extracts the signed integer literal of the specified size from an Addr.
func immI(a obj.Addr, nbits uint) uint32 {
if a.Type != obj.TYPE_CONST {
panic(fmt.Sprintf("ill typed: %+v", a))
}
if !immFits(a.Offset, nbits) {
panic(fmt.Sprintf("immediate %d in %v cannot fit in %d bits", a.Offset, a, nbits))
if !immIFits(a.Offset, nbits) {
panic(fmt.Sprintf("signed immediate %d in %v cannot fit in %d bits", a.Offset, a, nbits))
}
return uint32(a.Offset)
}
func wantImm(p *obj.Prog, pos string, a obj.Addr, nbits uint) {
// immU extracts the unsigned integer literal of the specified size from an Addr.
func immU(a obj.Addr, nbits uint) uint32 {
if a.Type != obj.TYPE_CONST {
panic(fmt.Sprintf("ill typed: %+v", a))
}
if !immUFits(a.Offset, nbits) {
panic(fmt.Sprintf("unsigned immediate %d in %v cannot fit in %d bits", a.Offset, a, nbits))
}
return uint32(a.Offset)
}
func wantImmI(p *obj.Prog, pos string, a obj.Addr, nbits uint) {
if a.Type != obj.TYPE_CONST {
p.Ctxt.Diag("%v\texpected immediate in %s position but got %s", p, pos, obj.Dconv(p, &a))
return
}
if !immFits(a.Offset, nbits) {
p.Ctxt.Diag("%v\timmediate in %s position cannot be larger than %d bits but got %d", p, pos, nbits, a.Offset)
if !immIFits(a.Offset, nbits) {
p.Ctxt.Diag("%v\tsigned immediate in %s position cannot be larger than %d bits but got %d", p, pos, nbits, a.Offset)
}
}
func wantImmU(p *obj.Prog, pos string, a obj.Addr, nbits uint) {
if a.Type != obj.TYPE_CONST {
p.Ctxt.Diag("%v\texpected immediate in %s position but got %s", p, pos, obj.Dconv(p, &a))
return
}
if !immUFits(a.Offset, nbits) {
p.Ctxt.Diag("%v\tunsigned immediate in %s position cannot be larger than %d bits but got %d", p, pos, nbits, a.Offset)
}
}
@ -296,29 +324,34 @@ func validateRFF(p *obj.Prog) {
}
func validateII(p *obj.Prog) {
wantImm(p, "from", p.From, 12)
wantImmI(p, "from", p.From, 12)
wantIntReg(p, "reg", p.Reg)
wantIntRegAddr(p, "to", &p.To)
}
func validateIF(p *obj.Prog) {
wantImm(p, "from", p.From, 12)
wantImmI(p, "from", p.From, 12)
wantIntReg(p, "reg", p.Reg)
wantFloatRegAddr(p, "to", &p.To)
}
func validateSI(p *obj.Prog) {
wantImm(p, "from", p.From, 12)
wantImmI(p, "from", p.From, 12)
wantIntReg(p, "reg", p.Reg)
wantIntRegAddr(p, "to", &p.To)
}
func validateSF(p *obj.Prog) {
wantImm(p, "from", p.From, 12)
wantImmI(p, "from", p.From, 12)
wantFloatReg(p, "reg", p.Reg)
wantIntRegAddr(p, "to", &p.To)
}
func validateU(p *obj.Prog) {
wantImmU(p, "from", p.From, 20)
wantIntRegAddr(p, "to", &p.To)
}
func validateRaw(p *obj.Prog) {
// Treat the raw value specially as a 32-bit unsigned integer.
// Nobody wants to enter negative machine code.
@ -395,11 +428,11 @@ func encodeIF(p *obj.Prog) uint32 {
func encodeS(p *obj.Prog, rs2 uint32) uint32 {
imm := immI(p.From, 12)
rs1 := regIAddr(p.To)
i := encode(p.As)
if i == nil {
ins := encode(p.As)
if ins == nil {
panic("encodeS: could not encode instruction")
}
return (imm>>5)<<25 | rs2<<20 | rs1<<15 | i.funct3<<12 | (imm&0x1f)<<7 | i.opcode
return (imm>>5)<<25 | rs2<<20 | rs1<<15 | ins.funct3<<12 | (imm&0x1f)<<7 | ins.opcode
}
func encodeSI(p *obj.Prog) uint32 {
@ -410,6 +443,21 @@ func encodeSF(p *obj.Prog) uint32 {
return encodeS(p, regF(p.Reg))
}
// encodeU encodes a U-type RISC-V instruction.
func encodeU(p *obj.Prog) uint32 {
// The immediates for encodeU are the upper 20 bits of a 32 bit value.
// Rather than have the user/compiler generate a 32 bit constant, the
// bottommost bits of which must all be zero, instead accept just the
// top bits.
imm := immU(p.From, 20)
rd := regIAddr(p.To)
ins := encode(p.As)
if ins == nil {
panic("encodeU: could not encode instruction")
}
return imm<<12 | rd<<7 | ins.opcode
}
// encodeRaw encodes a raw instruction value.
func encodeRaw(p *obj.Prog) uint32 {
// Treat the raw value specially as a 32-bit unsigned integer.
@ -455,6 +503,8 @@ var (
sIEncoding = encoding{encode: encodeSI, validate: validateSI, length: 4}
sFEncoding = encoding{encode: encodeSF, validate: validateSF, length: 4}
uEncoding = encoding{encode: encodeU, validate: validateU, length: 4}
// rawEncoding encodes a raw instruction byte sequence.
rawEncoding = encoding{encode: encodeRaw, validate: validateRaw, length: 4}
@ -483,6 +533,8 @@ var encodingForAs = [ALAST & obj.AMask]encoding{
ASLLI & obj.AMask: iIEncoding,
ASRLI & obj.AMask: iIEncoding,
ASRAI & obj.AMask: iIEncoding,
ALUI & obj.AMask: uEncoding,
AAUIPC & obj.AMask: uEncoding,
AADD & obj.AMask: rIIIEncoding,
ASLT & obj.AMask: rIIIEncoding,
ASLTU & obj.AMask: rIIIEncoding,