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unix: extend support for z/OS

Browse Source 
This change syncs the IBM internal version of sys/unix with the public
repository.

There are a variety of new syscalls and const definitions that have been
accumulated over the past few years to support developers using Go on
the platform. Old simulations of calls like 'epoll' and 'fstatfs' have
been replaced with their real counterparts. The zos/s390x syscalls also
have extensive trampolining to handle zos systems that might not have
support for some of these new system calls.

Closes golang/go#67071

Change-Id: I973d9e0abca2b05365308cf2b890438e50ae5957
Reviewed-on: https://go-review.googlesource.com/c/sys/+/582035
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Bill O'Farrell <billotosyr@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This commit is contained in:
dustin-ward
2024-05-03 20:28:26 +00:00
committed by Gopher Robot
parent 7758090324
commit 7d69d983c4
24 changed files with 12473 additions and 4405 deletions
Download Patch File Download Diff File Expand all files Collapse all files
unix/asm_zos_s390x.s
+317 -358
View File
@@ -9,9 +9,11 @@
#define PSALAA 1208(R0)
#define GTAB64(x) 80(x)
#define LCA64(x) 88(x)
#define SAVSTACK_ASYNC(x) 336(x) // in the LCA
#define CAA(x) 8(x)
#define EDCHPXV(x) 1016(x) // in the CAA
#define SAVSTACK_ASYNC(x) 336(x) // in the LCA
#define CEECAATHDID(x) 976(x) // in the CAA
#define EDCHPXV(x) 1016(x) // in the CAA
#define GOCB(x) 1104(x) // in the CAA
// SS_*, where x=SAVSTACK_ASYNC
#define SS_LE(x) 0(x)
@@ -19,394 +21,125 @@
#define SS_ERRNO(x) 16(x)
#define SS_ERRNOJR(x) 20(x)
#define LE_CALL BYTE $0x0D; BYTE $0x76; // BL R7, R6
// Function Descriptor Offsets
#define __errno 0x156*16
#define __err2ad 0x16C*16
TEXT ·clearErrno(SB),NOSPLIT,$0-0
BL addrerrno<>(SB)
MOVD $0, 0(R3)
// Call Instructions
#define LE_CALL BYTE $0x0D; BYTE $0x76 // BL R7, R6
#define SVC_LOAD BYTE $0x0A; BYTE $0x08 // SVC 08 LOAD
#define SVC_DELETE BYTE $0x0A; BYTE $0x09 // SVC 09 DELETE
DATA zosLibVec<>(SB)/8, $0
GLOBL zosLibVec<>(SB), NOPTR, $8
TEXT ·initZosLibVec(SB), NOSPLIT|NOFRAME, $0-0
MOVW PSALAA, R8
MOVD LCA64(R8), R8
MOVD CAA(R8), R8
MOVD EDCHPXV(R8), R8
MOVD R8, zosLibVec<>(SB)
RET
TEXT ·GetZosLibVec(SB), NOSPLIT|NOFRAME, $0-0
MOVD zosLibVec<>(SB), R8
MOVD R8, ret+0(FP)
RET
TEXT ·clearErrno(SB), NOSPLIT, $0-0
BL addrerrno<>(SB)
MOVD $0, 0(R3)
RET
// Returns the address of errno in R3.
TEXT addrerrno<>(SB),NOSPLIT|NOFRAME,$0-0
TEXT addrerrno<>(SB), NOSPLIT|NOFRAME, $0-0
// Get library control area (LCA).
MOVW PSALAA, R8
MOVD LCA64(R8), R8
MOVW PSALAA, R8
MOVD LCA64(R8), R8
// Get __errno FuncDesc.
MOVD CAA(R8), R9
MOVD EDCHPXV(R9), R9
ADD $(0x156*16), R9
LMG 0(R9), R5, R6
MOVD CAA(R8), R9
MOVD EDCHPXV(R9), R9
ADD $(__errno), R9
LMG 0(R9), R5, R6
// Switch to saved LE stack.
MOVD SAVSTACK_ASYNC(R8), R9
MOVD 0(R9), R4
MOVD $0, 0(R9)
MOVD SAVSTACK_ASYNC(R8), R9
MOVD 0(R9), R4
MOVD $0, 0(R9)
// Call __errno function.
LE_CALL
NOPH
// Switch back to Go stack.
XOR R0, R0 // Restore R0 to $0.
MOVD R4, 0(R9) // Save stack pointer.
RET
TEXT ·syscall_syscall(SB),NOSPLIT,$0-56
BL runtime·entersyscall(SB)
MOVD a1+8(FP), R1
MOVD a2+16(FP), R2
MOVD a3+24(FP), R3
// Get library control area (LCA).
MOVW PSALAA, R8
MOVD LCA64(R8), R8
// Get function.
MOVD CAA(R8), R9
MOVD EDCHPXV(R9), R9
MOVD trap+0(FP), R5
SLD $4, R5
ADD R5, R9
LMG 0(R9), R5, R6
// Restore LE stack.
MOVD SAVSTACK_ASYNC(R8), R9
MOVD 0(R9), R4
MOVD $0, 0(R9)
// Call function.
LE_CALL
NOPH
XOR R0, R0 // Restore R0 to $0.
MOVD R4, 0(R9) // Save stack pointer.
MOVD R3, r1+32(FP)
MOVD R0, r2+40(FP)
MOVD R0, err+48(FP)
MOVW R3, R4
CMP R4, $-1
BNE done
BL addrerrno<>(SB)
MOVWZ 0(R3), R3
MOVD R3, err+48(FP)
done:
BL runtime·exitsyscall(SB)
RET
TEXT ·syscall_rawsyscall(SB),NOSPLIT,$0-56
MOVD a1+8(FP), R1
MOVD a2+16(FP), R2
MOVD a3+24(FP), R3
// Get library control area (LCA).
MOVW PSALAA, R8
MOVD LCA64(R8), R8
// Get function.
MOVD CAA(R8), R9
MOVD EDCHPXV(R9), R9
MOVD trap+0(FP), R5
SLD $4, R5
ADD R5, R9
LMG 0(R9), R5, R6
// Restore LE stack.
MOVD SAVSTACK_ASYNC(R8), R9
MOVD 0(R9), R4
MOVD $0, 0(R9)
// Call function.
LE_CALL
NOPH
XOR R0, R0 // Restore R0 to $0.
MOVD R4, 0(R9) // Save stack pointer.
MOVD R3, r1+32(FP)
MOVD R0, r2+40(FP)
MOVD R0, err+48(FP)
MOVW R3, R4
CMP R4, $-1
BNE done
BL addrerrno<>(SB)
MOVWZ 0(R3), R3
MOVD R3, err+48(FP)
done:
RET
TEXT ·syscall_syscall6(SB),NOSPLIT,$0-80
BL runtime·entersyscall(SB)
MOVD a1+8(FP), R1
MOVD a2+16(FP), R2
MOVD a3+24(FP), R3
// Get library control area (LCA).
MOVW PSALAA, R8
MOVD LCA64(R8), R8
// Get function.
MOVD CAA(R8), R9
MOVD EDCHPXV(R9), R9
MOVD trap+0(FP), R5
SLD $4, R5
ADD R5, R9
LMG 0(R9), R5, R6
// Restore LE stack.
MOVD SAVSTACK_ASYNC(R8), R9
MOVD 0(R9), R4
MOVD $0, 0(R9)
// Fill in parameter list.
MOVD a4+32(FP), R12
MOVD R12, (2176+24)(R4)
MOVD a5+40(FP), R12
MOVD R12, (2176+32)(R4)
MOVD a6+48(FP), R12
MOVD R12, (2176+40)(R4)
// Call function.
LE_CALL
NOPH
XOR R0, R0 // Restore R0 to $0.
MOVD R4, 0(R9) // Save stack pointer.
MOVD R3, r1+56(FP)
MOVD R0, r2+64(FP)
MOVD R0, err+72(FP)
MOVW R3, R4
CMP R4, $-1
BNE done
BL addrerrno<>(SB)
MOVWZ 0(R3), R3
MOVD R3, err+72(FP)
done:
BL runtime·exitsyscall(SB)
RET
TEXT ·syscall_rawsyscall6(SB),NOSPLIT,$0-80
MOVD a1+8(FP), R1
MOVD a2+16(FP), R2
MOVD a3+24(FP), R3
// Get library control area (LCA).
MOVW PSALAA, R8
MOVD LCA64(R8), R8
// Get function.
MOVD CAA(R8), R9
MOVD EDCHPXV(R9), R9
MOVD trap+0(FP), R5
SLD $4, R5
ADD R5, R9
LMG 0(R9), R5, R6
// Restore LE stack.
MOVD SAVSTACK_ASYNC(R8), R9
MOVD 0(R9), R4
MOVD $0, 0(R9)
// Fill in parameter list.
MOVD a4+32(FP), R12
MOVD R12, (2176+24)(R4)
MOVD a5+40(FP), R12
MOVD R12, (2176+32)(R4)
MOVD a6+48(FP), R12
MOVD R12, (2176+40)(R4)
// Call function.
LE_CALL
NOPH
XOR R0, R0 // Restore R0 to $0.
MOVD R4, 0(R9) // Save stack pointer.
MOVD R3, r1+56(FP)
MOVD R0, r2+64(FP)
MOVD R0, err+72(FP)
MOVW R3, R4
CMP R4, $-1
BNE done
BL ·rrno<>(SB)
MOVWZ 0(R3), R3
MOVD R3, err+72(FP)
done:
RET
TEXT ·syscall_syscall9(SB),NOSPLIT,$0
BL runtime·entersyscall(SB)
MOVD a1+8(FP), R1
MOVD a2+16(FP), R2
MOVD a3+24(FP), R3
// Get library control area (LCA).
MOVW PSALAA, R8
MOVD LCA64(R8), R8
// Get function.
MOVD CAA(R8), R9
MOVD EDCHPXV(R9), R9
MOVD trap+0(FP), R5
SLD $4, R5
ADD R5, R9
LMG 0(R9), R5, R6
// Restore LE stack.
MOVD SAVSTACK_ASYNC(R8), R9
MOVD 0(R9), R4
MOVD $0, 0(R9)
// Fill in parameter list.
MOVD a4+32(FP), R12
MOVD R12, (2176+24)(R4)
MOVD a5+40(FP), R12
MOVD R12, (2176+32)(R4)
MOVD a6+48(FP), R12
MOVD R12, (2176+40)(R4)
MOVD a7+56(FP), R12
MOVD R12, (2176+48)(R4)
MOVD a8+64(FP), R12
MOVD R12, (2176+56)(R4)
MOVD a9+72(FP), R12
MOVD R12, (2176+64)(R4)
// Call function.
LE_CALL
NOPH
XOR R0, R0 // Restore R0 to $0.
MOVD R4, 0(R9) // Save stack pointer.
MOVD R3, r1+80(FP)
MOVD R0, r2+88(FP)
MOVD R0, err+96(FP)
MOVW R3, R4
CMP R4, $-1
BNE done
BL addrerrno<>(SB)
MOVWZ 0(R3), R3
MOVD R3, err+96(FP)
done:
BL runtime·exitsyscall(SB)
RET
TEXT ·syscall_rawsyscall9(SB),NOSPLIT,$0
MOVD a1+8(FP), R1
MOVD a2+16(FP), R2
MOVD a3+24(FP), R3
// Get library control area (LCA).
MOVW PSALAA, R8
MOVD LCA64(R8), R8
// Get function.
MOVD CAA(R8), R9
MOVD EDCHPXV(R9), R9
MOVD trap+0(FP), R5
SLD $4, R5
ADD R5, R9
LMG 0(R9), R5, R6
// Restore LE stack.
MOVD SAVSTACK_ASYNC(R8), R9
MOVD 0(R9), R4
MOVD $0, 0(R9)
// Fill in parameter list.
MOVD a4+32(FP), R12
MOVD R12, (2176+24)(R4)
MOVD a5+40(FP), R12
MOVD R12, (2176+32)(R4)
MOVD a6+48(FP), R12
MOVD R12, (2176+40)(R4)
MOVD a7+56(FP), R12
MOVD R12, (2176+48)(R4)
MOVD a8+64(FP), R12
MOVD R12, (2176+56)(R4)
MOVD a9+72(FP), R12
MOVD R12, (2176+64)(R4)
// Call function.
LE_CALL
NOPH
XOR R0, R0 // Restore R0 to $0.
MOVD R4, 0(R9) // Save stack pointer.
MOVD R3, r1+80(FP)
MOVD R0, r2+88(FP)
MOVD R0, err+96(FP)
MOVW R3, R4
CMP R4, $-1
BNE done
BL addrerrno<>(SB)
MOVWZ 0(R3), R3
MOVD R3, err+96(FP)
done:
XOR R0, R0 // Restore R0 to $0.
MOVD R4, 0(R9) // Save stack pointer.
RET
// func svcCall(fnptr unsafe.Pointer, argv *unsafe.Pointer, dsa *uint64)
TEXT ·svcCall(SB),NOSPLIT,$0
BL runtime·save_g(SB) // Save g and stack pointer
MOVW PSALAA, R8
MOVD LCA64(R8), R8
MOVD SAVSTACK_ASYNC(R8), R9
MOVD R15, 0(R9)
TEXT ·svcCall(SB), NOSPLIT, $0
BL runtime·save_g(SB) // Save g and stack pointer
MOVW PSALAA, R8
MOVD LCA64(R8), R8
MOVD SAVSTACK_ASYNC(R8), R9
MOVD R15, 0(R9)
MOVD argv+8(FP), R1 // Move function arguments into registers
MOVD dsa+16(FP), g
MOVD fnptr+0(FP), R15
MOVD argv+8(FP), R1 // Move function arguments into registers
MOVD dsa+16(FP), g
MOVD fnptr+0(FP), R15
BYTE $0x0D // Branch to function
BYTE $0xEF
BYTE $0x0D // Branch to function
BYTE $0xEF
BL runtime·load_g(SB) // Restore g and stack pointer
MOVW PSALAA, R8
MOVD LCA64(R8), R8
MOVD SAVSTACK_ASYNC(R8), R9
MOVD 0(R9), R15
BL runtime·load_g(SB) // Restore g and stack pointer
MOVW PSALAA, R8
MOVD LCA64(R8), R8
MOVD SAVSTACK_ASYNC(R8), R9
MOVD 0(R9), R15
RET
// func svcLoad(name *byte) unsafe.Pointer
TEXT ·svcLoad(SB),NOSPLIT,$0
MOVD R15, R2 // Save go stack pointer
MOVD name+0(FP), R0 // Move SVC args into registers
MOVD $0x80000000, R1
MOVD $0, R15
BYTE $0x0A // SVC 08 LOAD
BYTE $0x08
MOVW R15, R3 // Save return code from SVC
MOVD R2, R15 // Restore go stack pointer
CMP R3, $0 // Check SVC return code
BNE error
TEXT ·svcLoad(SB), NOSPLIT, $0
MOVD R15, R2 // Save go stack pointer
MOVD name+0(FP), R0 // Move SVC args into registers
MOVD $0x80000000, R1
MOVD $0, R15
SVC_LOAD
MOVW R15, R3 // Save return code from SVC
MOVD R2, R15 // Restore go stack pointer
CMP R3, $0 // Check SVC return code
BNE error
MOVD $-2, R3 // Reset last bit of entry point to zero
AND R0, R3
MOVD R3, addr+8(FP) // Return entry point returned by SVC
CMP R0, R3 // Check if last bit of entry point was set
BNE done
MOVD $-2, R3 // Reset last bit of entry point to zero
AND R0, R3
MOVD R3, ret+8(FP) // Return entry point returned by SVC
CMP R0, R3 // Check if last bit of entry point was set
BNE done
MOVD R15, R2 // Save go stack pointer
MOVD $0, R15 // Move SVC args into registers (entry point still in r0 from SVC 08)
BYTE $0x0A // SVC 09 DELETE
BYTE $0x09
MOVD R2, R15 // Restore go stack pointer
MOVD R15, R2 // Save go stack pointer
MOVD $0, R15 // Move SVC args into registers (entry point still in r0 from SVC 08)
SVC_DELETE
MOVD R2, R15 // Restore go stack pointer
error:
MOVD $0, addr+8(FP) // Return 0 on failure
MOVD $0, ret+8(FP) // Return 0 on failure
done:
XOR R0, R0 // Reset r0 to 0
XOR R0, R0 // Reset r0 to 0
RET
// func svcUnload(name *byte, fnptr unsafe.Pointer) int64
TEXT ·svcUnload(SB),NOSPLIT,$0
MOVD R15, R2 // Save go stack pointer
MOVD name+0(FP), R0 // Move SVC args into registers
MOVD addr+8(FP), R15
BYTE $0x0A // SVC 09
BYTE $0x09
XOR R0, R0 // Reset r0 to 0
MOVD R15, R1 // Save SVC return code
MOVD R2, R15 // Restore go stack pointer
MOVD R1, rc+0(FP) // Return SVC return code
TEXT ·svcUnload(SB), NOSPLIT, $0
MOVD R15, R2 // Save go stack pointer
MOVD name+0(FP), R0 // Move SVC args into registers
MOVD fnptr+8(FP), R15
SVC_DELETE
XOR R0, R0 // Reset r0 to 0
MOVD R15, R1 // Save SVC return code
MOVD R2, R15 // Restore go stack pointer
MOVD R1, ret+16(FP) // Return SVC return code
RET
// func gettid() uint64
@@ -417,7 +150,233 @@ TEXT ·gettid(SB), NOSPLIT, $0
// Get CEECAATHDID
MOVD CAA(R8), R9
MOVD 0x3D0(R9), R9
MOVD CEECAATHDID(R9), R9
MOVD R9, ret+0(FP)
RET
//
// Call LE function, if the return is -1
// errno and errno2 is retrieved
//
TEXT ·CallLeFuncWithErr(SB), NOSPLIT, $0
MOVW PSALAA, R8
MOVD LCA64(R8), R8
MOVD CAA(R8), R9
MOVD g, GOCB(R9)
// Restore LE stack.
MOVD SAVSTACK_ASYNC(R8), R9 // R9-> LE stack frame saving address
MOVD 0(R9), R4 // R4-> restore previously saved stack frame pointer
MOVD parms_base+8(FP), R7 // R7 -> argument array
MOVD parms_len+16(FP), R8 // R8 number of arguments
// arg 1 ---> R1
CMP R8, $0
BEQ docall
SUB $1, R8
MOVD 0(R7), R1
// arg 2 ---> R2
CMP R8, $0
BEQ docall
SUB $1, R8
ADD $8, R7
MOVD 0(R7), R2
// arg 3 --> R3
CMP R8, $0
BEQ docall
SUB $1, R8
ADD $8, R7
MOVD 0(R7), R3
CMP R8, $0
BEQ docall
MOVD $2176+16, R6 // starting LE stack address-8 to store 4th argument
repeat:
ADD $8, R7
MOVD 0(R7), R0 // advance arg pointer by 8 byte
ADD $8, R6 // advance LE argument address by 8 byte
MOVD R0, (R4)(R6*1) // copy argument from go-slice to le-frame
SUB $1, R8
CMP R8, $0
BNE repeat
docall:
MOVD funcdesc+0(FP), R8 // R8-> function descriptor
LMG 0(R8), R5, R6
MOVD $0, 0(R9) // R9 address of SAVSTACK_ASYNC
LE_CALL // balr R7, R6 (return #1)
NOPH
MOVD R3, ret+32(FP)
CMP R3, $-1 // compare result to -1
BNE done
// retrieve errno and errno2
MOVD zosLibVec<>(SB), R8
ADD $(__errno), R8
LMG 0(R8), R5, R6
LE_CALL // balr R7, R6 __errno (return #3)
NOPH
MOVWZ 0(R3), R3
MOVD R3, err+48(FP)
MOVD zosLibVec<>(SB), R8
ADD $(__err2ad), R8
LMG 0(R8), R5, R6
LE_CALL // balr R7, R6 __err2ad (return #2)
NOPH
MOVW (R3), R2 // retrieve errno2
MOVD R2, errno2+40(FP) // store in return area
done:
MOVD R4, 0(R9) // Save stack pointer.
RET
//
// Call LE function, if the return is 0
// errno and errno2 is retrieved
//
TEXT ·CallLeFuncWithPtrReturn(SB), NOSPLIT, $0
MOVW PSALAA, R8
MOVD LCA64(R8), R8
MOVD CAA(R8), R9
MOVD g, GOCB(R9)
// Restore LE stack.
MOVD SAVSTACK_ASYNC(R8), R9 // R9-> LE stack frame saving address
MOVD 0(R9), R4 // R4-> restore previously saved stack frame pointer
MOVD parms_base+8(FP), R7 // R7 -> argument array
MOVD parms_len+16(FP), R8 // R8 number of arguments
// arg 1 ---> R1
CMP R8, $0
BEQ docall
SUB $1, R8
MOVD 0(R7), R1
// arg 2 ---> R2
CMP R8, $0
BEQ docall
SUB $1, R8
ADD $8, R7
MOVD 0(R7), R2
// arg 3 --> R3
CMP R8, $0
BEQ docall
SUB $1, R8
ADD $8, R7
MOVD 0(R7), R3
CMP R8, $0
BEQ docall
MOVD $2176+16, R6 // starting LE stack address-8 to store 4th argument
repeat:
ADD $8, R7
MOVD 0(R7), R0 // advance arg pointer by 8 byte
ADD $8, R6 // advance LE argument address by 8 byte
MOVD R0, (R4)(R6*1) // copy argument from go-slice to le-frame
SUB $1, R8
CMP R8, $0
BNE repeat
docall:
MOVD funcdesc+0(FP), R8 // R8-> function descriptor
LMG 0(R8), R5, R6
MOVD $0, 0(R9) // R9 address of SAVSTACK_ASYNC
LE_CALL // balr R7, R6 (return #1)
NOPH
MOVD R3, ret+32(FP)
CMP R3, $0 // compare result to 0
BNE done
// retrieve errno and errno2
MOVD zosLibVec<>(SB), R8
ADD $(__errno), R8
LMG 0(R8), R5, R6
LE_CALL // balr R7, R6 __errno (return #3)
NOPH
MOVWZ 0(R3), R3
MOVD R3, err+48(FP)
MOVD zosLibVec<>(SB), R8
ADD $(__err2ad), R8
LMG 0(R8), R5, R6
LE_CALL // balr R7, R6 __err2ad (return #2)
NOPH
MOVW (R3), R2 // retrieve errno2
MOVD R2, errno2+40(FP) // store in return area
XOR R2, R2
MOVWZ R2, (R3) // clear errno2
done:
MOVD R4, 0(R9) // Save stack pointer.
RET
//
// function to test if a pointer can be safely dereferenced (content read)
// return 0 for succces
//
TEXT ·ptrtest(SB), NOSPLIT, $0-16
MOVD arg+0(FP), R10 // test pointer in R10
// set up R2 to point to CEECAADMC
BYTE $0xE3; BYTE $0x20; BYTE $0x04; BYTE $0xB8; BYTE $0x00; BYTE $0x17 // llgt 2,1208
BYTE $0xB9; BYTE $0x17; BYTE $0x00; BYTE $0x22 // llgtr 2,2
BYTE $0xA5; BYTE $0x26; BYTE $0x7F; BYTE $0xFF // nilh 2,32767
BYTE $0xE3; BYTE $0x22; BYTE $0x00; BYTE $0x58; BYTE $0x00; BYTE $0x04 // lg 2,88(2)
BYTE $0xE3; BYTE $0x22; BYTE $0x00; BYTE $0x08; BYTE $0x00; BYTE $0x04 // lg 2,8(2)
BYTE $0x41; BYTE $0x22; BYTE $0x03; BYTE $0x68 // la 2,872(2)
// set up R5 to point to the "shunt" path which set 1 to R3 (failure)
BYTE $0xB9; BYTE $0x82; BYTE $0x00; BYTE $0x33 // xgr 3,3
BYTE $0xA7; BYTE $0x55; BYTE $0x00; BYTE $0x04 // bras 5,lbl1
BYTE $0xA7; BYTE $0x39; BYTE $0x00; BYTE $0x01 // lghi 3,1
// if r3 is not zero (failed) then branch to finish
BYTE $0xB9; BYTE $0x02; BYTE $0x00; BYTE $0x33 // lbl1 ltgr 3,3
BYTE $0xA7; BYTE $0x74; BYTE $0x00; BYTE $0x08 // brc b'0111',lbl2
// stomic store shunt address in R5 into CEECAADMC
BYTE $0xE3; BYTE $0x52; BYTE $0x00; BYTE $0x00; BYTE $0x00; BYTE $0x24 // stg 5,0(2)
// now try reading from the test pointer in R10, if it fails it branches to the "lghi" instruction above
BYTE $0xE3; BYTE $0x9A; BYTE $0x00; BYTE $0x00; BYTE $0x00; BYTE $0x04 // lg 9,0(10)
// finish here, restore 0 into CEECAADMC
BYTE $0xB9; BYTE $0x82; BYTE $0x00; BYTE $0x99 // lbl2 xgr 9,9
BYTE $0xE3; BYTE $0x92; BYTE $0x00; BYTE $0x00; BYTE $0x00; BYTE $0x24 // stg 9,0(2)
MOVD R3, ret+8(FP) // result in R3
RET
//
// function to test if a untptr can be loaded from a pointer
// return 1: the 8-byte content
// 2: 0 for success, 1 for failure
//
// func safeload(ptr uintptr) ( value uintptr, error uintptr)
TEXT ·safeload(SB), NOSPLIT, $0-24
MOVD ptr+0(FP), R10 // test pointer in R10
MOVD $0x0, R6
BYTE $0xE3; BYTE $0x20; BYTE $0x04; BYTE $0xB8; BYTE $0x00; BYTE $0x17 // llgt 2,1208
BYTE $0xB9; BYTE $0x17; BYTE $0x00; BYTE $0x22 // llgtr 2,2
BYTE $0xA5; BYTE $0x26; BYTE $0x7F; BYTE $0xFF // nilh 2,32767
BYTE $0xE3; BYTE $0x22; BYTE $0x00; BYTE $0x58; BYTE $0x00; BYTE $0x04 // lg 2,88(2)
BYTE $0xE3; BYTE $0x22; BYTE $0x00; BYTE $0x08; BYTE $0x00; BYTE $0x04 // lg 2,8(2)
BYTE $0x41; BYTE $0x22; BYTE $0x03; BYTE $0x68 // la 2,872(2)
BYTE $0xB9; BYTE $0x82; BYTE $0x00; BYTE $0x33 // xgr 3,3
BYTE $0xA7; BYTE $0x55; BYTE $0x00; BYTE $0x04 // bras 5,lbl1
BYTE $0xA7; BYTE $0x39; BYTE $0x00; BYTE $0x01 // lghi 3,1
BYTE $0xB9; BYTE $0x02; BYTE $0x00; BYTE $0x33 // lbl1 ltgr 3,3
BYTE $0xA7; BYTE $0x74; BYTE $0x00; BYTE $0x08 // brc b'0111',lbl2
BYTE $0xE3; BYTE $0x52; BYTE $0x00; BYTE $0x00; BYTE $0x00; BYTE $0x24 // stg 5,0(2)
BYTE $0xE3; BYTE $0x6A; BYTE $0x00; BYTE $0x00; BYTE $0x00; BYTE $0x04 // lg 6,0(10)
BYTE $0xB9; BYTE $0x82; BYTE $0x00; BYTE $0x99 // lbl2 xgr 9,9
BYTE $0xE3; BYTE $0x92; BYTE $0x00; BYTE $0x00; BYTE $0x00; BYTE $0x24 // stg 9,0(2)
MOVD R6, value+8(FP) // result in R6
MOVD R3, error+16(FP) // error in R3
RET