In FFICallbackThunk>>initializeRiscV64
(gdb) n
571		memmove(((void *)dest), ((void *)src), (stop - start) + 1);
(gdb) p dest
$8 = 274727944192  ## Address of start of thunk code (see below)
(gdb) n
575		methodReturnReceiver();
(gdb) x 274727944192
0x3ff70fc000:	0x97020000
(gdb) break 0x3ff70fc000  # try to break in thunk code
Function "0x3ff70fc000" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 3 (0x3ff70fc000) pending.
(gdb) cont
Continuing.
... ... ...
Thread 1 "squeak" received signal SIGILL, Illegal instruction.
0x0000003ff70fc000 in ?? ()
(gdb) bt
#0  0x0000003ff70fc000 in ?? ()
(gdb) x/20 0x0000003ff70fc000 
 ## thunk code; primThunkEntryAddress is 0x2aaab68052
0x3ff70fc000:	0x97020000	0x16e40111	0x01000ae0	0x030017c3
0x3ff70fc010:	0x82938333	0x0561c260	0x01008280	0x01000100
0x3ff70fc020:	0x00000000	0x00000000	0xaab68052	0x0000002a
0x3ff70fc030:	0x00000000	0x00000000	0x00000000	0x00000000
0x3ff70fc040:	0x00000000	0x00000000	0x00000000	0x00000000
(gdb) i r
ra             0x3ff7e4db30	0x3ff7e4db30 <msort_with_tmp+122>
sp             0x3ffffcb2e0	0x3ffffcb2e0
gp             0x2aaabf1378	0x2aaabf1378 <extraRoots+128>
tp             0x3ff7e1b7b0	0x3ff7e1b7b0
t0             0x1	1
t1             0x3ff7e4def4	274741911284
t2             0x3ff	1023
fp             0x3ffffcb580	0x3ffffcb580
s1             0x2aaacebb90	183254301584
a0             0x2aaacebb88	183254301576
a1             0x2aaacebb90	183254301584
a2             0x0	0
a3             0x0	0
a4             0x2	2
a5             0x1	1
a6             0x0	0
a7             0x0	0
s2             0x1	1
s3             0x1	1

=================
"
  0 :	00000297        auipc	t0,0x0       Current PC = self codeAddress
  4 :	1101            addi	sp,sp,-32   reserve 4 stack slots (1 for alignment)
  6 :	e806            sd	ra,16(sp)	push Return Address
  8 :	e416            sd	t0,8(sp)	push self codeAddress
  a :	e00a            sd	sp,0(sp)	push current Stack Pointer
  c :	0001C317        auipc	t1,0x1C	PC+0x1C is address of &entryThunk
 10:	00033383        ld	t2,0(t1)	get &entryThunk in register
 12 :	9382            jalr	t2			Call entryThunk()
 14 :	60c2            ld	ra,16(sp)	Restore saved Return Address
 16 :	6105            addi	sp,sp,32	Restore Stack Pointer
 18 :	8082            ret	Return to Mamma
 1a :	0001            nop	--keep prefetch happy--
...
 28:   <@entryThunk>
"
	| bytes |
	bytes := #[16r00 16r00 16r02 16r97
				16r11 16r01
				16rE4 16r16
				16rE0 16r0A
				16r00 16r01 16rC3 16r17
				16r00 16r03 16r33 16r83
				16r93 16r82
				16r60 16rC2
				16r61 16r05
				16r80 16r82
				16r00 16r01
				0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] copy.
	bytes unsignedLongLongAt: 41 put: self primThunkEntryAddress.
	self replaceFrom: 1 to: 48 with: bytes startingAt: 1.