v86/src/rust/paging.rs

macro_rules! return_on_pagefault {
    ($expr:expr) => {
        match $expr {
            Ok(v) => v,
            Err(()) => return,
        }
    };
}
Handle pagefaults without JS exceptions This commit makes the return type of most basic memory access primitives Result, where the Err(()) case means a page fault happened, the instruction should be aborted and execution should continue at the page fault handler. The following primites have a Result return type: safe_{read,write}, translate_address_, read_imm, writable_or_pagefault, get_phys_eip, modrm_resolve, push, pop*. Any instruction needs to handle the page fault cases and abort execution appropriately. The return_on_pagefault! macro has been provided to get the same behaviour as the previously used JS exceptions (local to the function). Calls from JavaScript abort on a pagefault, except for writable_or_pagefault, which returns a boolean. JS needs to check before calling any function that may pagefault. This commit does not yet pervasively apply return_on_pagefault!, this will be added in the next commit. Jitted code does not yet properly handle the new form of page faults, this will be added in a later commit. 2018-08-14 23:07:54 +02:00			`macro_rules! return_on_pagefault {`
			`($expr:expr) => {`
			`match $expr {`
			`Ok(v) => v,`
			`Err(()) => return,`
			`}`
			`};`
			`}`