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update comments a bit

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Rett Berg 2019-11-16 12:44:47 -07:00
parent b27d3a088d
commit 4727925b1a
1 changed files with 9 additions and 10 deletions
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@ -223,7 +223,12 @@ contributors:
) )
(export "apply_cos64" (func $apply_cos64)) (export "apply_cos64" (func $apply_cos64))
;; Demonstration of how this C code might be written by hand ;; 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
;; approach is to use a mutable global to store the stack_ptr. We give
;; ourselves 1MiB of mem-stack and grow it downwards.
;;
;; Below is a demonstration of how this C code **might** be written by hand
;; ;;
;; typedef struct { ;; typedef struct {
;; int a; ;; int a;
@ -238,17 +243,11 @@ contributors:
;; sum_struct_t s = sum_struct_create(40, 2); ;; sum_struct_t s = sum_struct_create(40, 2);
;; return s.a + s.b; ;; return s.a + s.b;
;; } ;; }
;;
;; Wasm is a stack-based language, but for returning values more complicated ;; Unlike C, we must manage our own memory stack
;; than an int/float, a memory stack has to be manually managed. One ;;
;; approach is to use a mutable global to store the stack_ptr. We give
;; ourselves 1MiB of mem-stack and grow it downwards.
;;
;; Note: we are differentiating from the memstack (stack stored in memory)
;; and the "stack", which wasm implicitly uses to to pass and return values.
(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
(func $sum_struct_create (func $sum_struct_create
(param $sum_struct_ptr i32) (param $sum_struct_ptr i32)
(param $var$a i32) (param $var$a i32)