iskm/learnxinyminutes-docs
1
0
Fork 0
mirror of https://github.com/adambard/learnxinyminutes-docs.git synced 2024-12-23 17:41:41 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

more comment updates

Browse Source
This commit is contained in:
Rett Berg 2019-11-16 12:47:32 -07:00
parent 4727925b1a
commit 0427cb3168
1 changed files with 6 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
wasm.html.markdown
View File

@ -224,9 +224,9 @@ contributors:
(export "apply_cos64" (func $apply_cos64)) (export "apply_cos64" (func $apply_cos64))
;; Wasm is a stack-based language, but for returning values more complicated ;; Wasm is a stack-based language, but for returning values more complicated
;; than an int/float, a memory stack has to be manually managed. One ;; than an int/float, a separate memory stack has to be manually managed. One
;; approach is to use a mutable global to store the stack_ptr. We give ;; approach is to use a mutable global to store the stack_ptr. We give
;; ourselves 1MiB of mem-stack and grow it downwards. ;; ourselves 1MiB of memstack and grow it downwards.
;; ;;
;; Below is a demonstration of how this C code **might** be written by hand ;; Below is a demonstration of how this C code **might** be written by hand
;; ;;
@ -244,7 +244,7 @@ contributors:
;; return s.a + s.b; ;; return s.a + s.b;
;; } ;; }
;; Unlike C, we must manage our own memory stack ;; Unlike C, we must manage our own memory stack. We reserve 1MiB
(global $memstack_ptr (mut i32) (i32.const 65536)) (global $memstack_ptr (mut i32) (i32.const 65536))
;; Structs can only be returned by reference ;; Structs can only be returned by reference
@ -270,7 +270,7 @@ contributors:
(local $var$sum_struct$b i32) (local $var$sum_struct$b i32)
(local $local_memstack_ptr i32) (local $local_memstack_ptr i32)
;; reserve stack space ;; reserve memstack space
(i32.sub (i32.sub
(get_global $memstack_ptr) (get_global $memstack_ptr)
(i32.const 8) (i32.const 8)
@ -278,7 +278,7 @@ contributors:
tee_local $local_memstack_ptr ;; tee both stores and returns given value tee_local $local_memstack_ptr ;; tee both stores and returns given value
set_global $memstack_ptr set_global $memstack_ptr
;; call the function, storing the result in the stack ;; call the function, storing the result in the memstack
(call $sum_struct_create (call $sum_struct_create
((;$sum_struct_ptr=;) get_local $local_memstack_ptr) ((;$sum_struct_ptr=;) get_local $local_memstack_ptr)
((;$var$a=;) i32.const 40) ((;$var$a=;) i32.const 40)
@ -293,7 +293,7 @@ contributors:
(i32.load offset=4 (get_local $local_memstack_ptr)) (i32.load offset=4 (get_local $local_memstack_ptr))
) )
;; unreserve stack space ;; unreserve memstack space
(set_global $memstack_ptr (set_global $memstack_ptr
(i32.add (i32.add
(get_local $local_memstack_ptr) (get_local $local_memstack_ptr)