diff options
Diffstat (limited to '05/codegen.b')
| -rw-r--r-- | 05/codegen.b | 31 |
1 files changed, 28 insertions, 3 deletions
diff --git a/05/codegen.b b/05/codegen.b index 1507e6d..2cd000c 100644 --- a/05/codegen.b +++ b/05/codegen.b @@ -1,7 +1,18 @@ ; CALLING CONVENTION: -; arguments are pushed onto the stack by the caller, from right to left -; caller must also reserve space on stack for return value -; so the function puts the return value at [rbp+8] (+8 for stored return address) +; Here is the process for calling a function: +; - the caller pushes the arguments on to the stack, from right to left +; - the caller subtracts sizeof(return type) from rsp +; - the caller calls the function +; - the caller stores away the return value +; - the caller adds (sizeof(return type) + sizeof arg0 + ... + sizeof argn) to rsp +; STACK LAYOUT: +; arg n +; ... +; arg 0 +; return value [rbp+16] +; return address [rbp+8] +; old rbp [rbp] +; local variables @@ -191,5 +202,19 @@ function generate_code codegen_second_pass = 1 generate_functions() ; generate code at the entry point of the executable + local main_addr + main_addr = ident_list_lookup(functions_addresses, .str_main) + if main_addr == 0 goto no_main_function + + ; on entry, we will have: + ; argc = *rsp + ; argv = rsp + 8 + + ; @TODO return + :no_main_function + die(.str_no_main_function) + :str_no_main_function + string Error: No main function. + byte 0 |