Backtrace implementation for x86-64:

(backtrace,
aa
f prev @ rsp
f base@ rbp
loop:
f next @ `pq 1 @base~[1]`,
f cont @ `pq 1 @base+8~[1]`,
?= next
??()
?= next-0xffffffffffffffff
??()
?= cont-0xffffffffffffffff
??()
?e StackFrame at `?v next` with size `?vi base-prev`
x base-prev@base+16
?e Code: `?v cont`
pdf @ cont
f prev@base
f base@next
.loop:
)
.(backtrace)