Use mips64 instead of mips

For GOARCH=mips the Go compiler will use the newer MIPS32-r1 ISA,
whereas for GOARCH=mips64 it will use the MIPS-III ISA, which is the
highest N64 supports.

See golang#60072

Author: clktmr

src/cmd/dist/build.go

@@ -1630,7 +1630,7 @@ var cgoEnabled = map[string]bool{
 	"windows/arm64":   true,
 	"noos/thumb":      false,
 	"noos/riscv64":    false,
-	"noos/mips":       false,
+	"noos/mips64":     false,
 }
 
 // List of platforms which are supported but not complete yet. These get

src/cmd/link/internal/mips/obj.go

@@ -88,15 +88,5 @@ func archinit(ctxt *ld.Link) {
 		if *ld.FlagRound == -1 {
 			*ld.FlagRound = 0x10000
 		}
-	case objabi.Hnoos:
-		*ld.FlagD = true
-		ld.Elfinit(ctxt)
-		ld.HEADR = ld.ELFRESERVE
-		if *ld.FlagTextAddr == -1 {
-			*ld.FlagTextAddr = 0
-		}
-		if *ld.FlagRound == -1 {
-			*ld.FlagRound = 8
-		}
 	}
 }

src/cmd/link/internal/mips64/obj.go

@@ -98,5 +98,15 @@ func archinit(ctxt *ld.Link) {
 		if *ld.FlagRound == -1 {
 			*ld.FlagRound = 0x10000
 		}
+	case objabi.Hnoos:
+		*ld.FlagD = true
+		ld.Elfinit(ctxt)
+		ld.HEADR = ld.ELFRESERVE
+		if *ld.FlagTextAddr == -1 {
+			*ld.FlagTextAddr = 0
+		}
+		if *ld.FlagRound == -1 {
+			*ld.FlagRound = 8
+		}
 	}
 }

src/runtime/asm_mips64x.s

@@ -11,6 +11,8 @@
 
 #define	REGCTXT	R22
 
+#ifndef GOOS_noos
+
 TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
 	// R29 = stack; R4 = argc; R5 = argv
 
@@ -74,6 +76,8 @@ nocgo:
 	MOVV	R0, 1(R0)
 	RET
 
+#endif
+
 DATA	runtime·mainPC+0(SB)/8,$runtime·main(SB)
 GLOBL	runtime·mainPC(SB),RODATA,$8
 

src/runtime/asm_mipsx.s

@@ -11,8 +11,6 @@
 
 #define	REGCTXT	R22
 
-#ifndef GOOS_noos
-
 TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
 	// R29 = stack; R4 = argc; R5 = argv
 
@@ -77,8 +75,6 @@ nocgo:
 	UNDEF
 	RET
 
-#endif
-
 DATA	runtime·mainPC+0(SB)/4,$runtime·main(SB)
 GLOBL	runtime·mainPC(SB),RODATA,$4
 

src/runtime/mksizeclasses_mcu64.go

@@ -52,7 +52,7 @@ func main() {
 	fmt.Fprintln(&b, "// Code generated by mksizeclasses_mcu64.go; DO NOT EDIT.")
 	fmt.Fprintln(&b, "//go:generate go run mksizeclasses_mcu64.go")
 	fmt.Fprintln(&b)
-	fmt.Fprintln(&b, "//go:build noos && riscv64")
+	fmt.Fprintln(&b, "//go:build noos && (riscv64 || mips64)")
 	fmt.Fprintln(&b)
 	fmt.Fprintln(&b, "package runtime")
 	classes := makeClasses()

src/runtime/os_noos_mips.go renamed to src/runtime/os_noos_mips64.go

@@ -8,7 +8,7 @@
 #include "textflag.h"
 
 
-TEXT _rt0_mips_noos(SB),NOSPLIT|NOFRAME,$0
+TEXT _rt0_mips64_noos(SB),NOSPLIT|NOFRAME,$0
 	// TODO implement
 	RET