all looks ok

1 files changed, 58 insertions, 2 deletions

diff --git a/include/data.s b/include/data.s
index 4a827e2..35c4c8d 100644
--- a/include/data.s
+++ b/include/data.s
@@ -1,7 +1,7 @@
 
 .ifndef _data_s_file
 _data_s_file:
-	nop
+	nop # avoid confusing gdb
 
 # Format of the info tables:
 # - code
@@ -64,6 +64,62 @@ IND_info:
 IND_code:
 	enter 010(%rbp)
 
+# Blackhole (contains the original thunkptr for debugging purposes)
+# | ptr | orig_thunkptr |
+BLE_evacuate:
+	jmp _gc_evacuate_ret
+BLE_scavenge:
+	jmp _gc_scavenge_ret
+
+BLE_info_table:
+	cell BLE_evacuate
+	cell BLE_scavenge
+	cell 0
+BLE_code:
+	# if we hit this, we've got a pure loop in a program, and it is never
+	# going to actually progress. So let's just shoot it down with a
+	# helpful message or so.
+	mov 010(%rbp), %r15
+
+	mov $1, %rdi #stdout
+
+	mov $14, %rdx
+	mov $BLE_msg, %rsi
+	mov $1, %rax #write
+	syscall
+
+	mov $1, %rdx
+	BLE_loop:
+	mov %r15, %rcx
+	and $0xf, %rcx
+	mov $BLE_hex, %rsi
+	add %rcx, %rsi
+	mov $1, %rax
+	syscall
+	shr $4, %r15
+	jnz BLE_loop
+
+	mov $BLE_nl, %rsi
+	mov $1, %rax
+	syscall
+
+	# shot self down (and retry if it doesn't succeed)
+	BLE_retry_sigkill:
+	mov $39, %rax
+	syscall # getpid
+	mov %rax, %rdi
+	mov $6, %rsi # SIGABRT
+	mov $62, %rax # kill
+	syscall
+	jmp BLE_retry_sigkill
+
+BLE_msg:
+	.ascii "diverged at 0x"
+BLE_hex:
+	.ascii "0123456789abcdef"
+BLE_nl:
+	.ascii "\n"
+
 # List
 # | ptr | 0 |           # [] case
 # | ptr | 1 | a | b |   # (a:b) case
@@ -86,7 +142,7 @@ LIST_scavenge:
 	cmpq $0, 010(%rbp)
 	je LIST_scavenge_nil
 	mov %rbp, %r15
-	
+
 	mov $LIST_scavenge1, %rsi
 	mov 020(%r15), %rbp
 	jmp _gc_evacuate