From bcba0c88f4eaddac8e0d8c0fa68264b2e81ee272 Mon Sep 17 00:00:00 2001
From: Jonas Hvid <mail@johv.dk>
Date: Sun, 4 Oct 2020 01:40:36 +0200
Subject: [PATCH] Rename UEFI procedures to generic naming scheme

---
 main.asm    | 27 +++++++++++++++++++++++----
 os/uefi.asm | 23 +++++++----------------
 2 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/main.asm b/main.asm
index 0190d18..5985b99 100644
--- a/main.asm
+++ b/main.asm
@@ -1,5 +1,24 @@
 ;; vim: syntax=fasm
 
+;; At compile-time we load the module given by the environment variable
+;; OS_INCLUDE. This module should define the following macros:
+;;
+;; Each of these functions should preserve the value of RSI and RSP. They may
+;; use other registers as they like.
+;;
+;; os_initialize
+;;   Called at initialization.
+;;
+;; os_print_string
+;;   Takes a string buffer in RCX and the length in RDX, and prints the string
+;;   to the console.
+;;
+;; os_read_char
+;;   Wait for the user to type a key, and then put the corresponding ASCII byte
+;;   into the buffer pointed to by RCX.
+;;
+;; os_terminate
+;;   Shut down the system.
 include '%OS_INCLUDE%'
 
 ;; Print a string of a given length.
@@ -14,7 +33,7 @@ macro sys_print_string {
   push r9
   push r10
 
-  call uefi_print_string
+  call os_print_string
 
   pop r10
   pop r9
@@ -38,7 +57,7 @@ macro sys_read_char {
   push r15
 
   mov rcx, rsi
-  call uefi_read_char
+  call os_read_char
 
   pop r15
   pop r10
@@ -49,7 +68,7 @@ macro sys_read_char {
 
 macro sys_terminate code {
   mov rax, code
-  call uefi_terminate
+  call os_terminate
 }
 
 ;; The code in this macro is placed at the end of each Forth word. When we are
@@ -118,7 +137,7 @@ main:
   cld                        ; Clear direction flag so LODSQ does the right thing.
   mov rbp, return_stack_top  ; Initialize return stack
 
-  call uefi_initialize
+  call os_initialize
 
   mov rax, MAIN
   jmp qword [rax]
diff --git a/os/uefi.asm b/os/uefi.asm
index d116b2c..4f8ce56 100644
--- a/os/uefi.asm
+++ b/os/uefi.asm
@@ -60,17 +60,12 @@ struct EFI_INPUT_KEY
 
 section '.text' code executable readable
 
-uefi_initialize:
+os_initialize:
   ; At program startup, RDX contains an EFI_SYSTEM_TABLE*.
   mov [system_table], rdx
   ret
 
-;; Print a string of the given length.
-;;
-;; Inputs:
-;;  - RCX = String buffer
-;;  - RDX = String length
-uefi_print_string:
+os_print_string:
   ;; We take an input string of bytes without any terminator. We need to turn
   ;; this string into a string of words, terminated by a null character.
 
@@ -133,11 +128,7 @@ uefi_print_string:
   add rsp, 32
   ret
 
-;; Read a character as an ASCII byte into the given buffer.
-;;
-;; Inputs:
-;; - RCX = Character buffer (1 byte)
-uefi_read_char:
+os_read_char:
   mov r15, rcx
 .read_key:
   mov rcx, [system_table]                                       ; EFI_SYSTEM_TABLE* rcx
@@ -164,7 +155,7 @@ uefi_read_char:
   ;; Print the character
   mov rcx, r15
   mov rdx, 1
-  call uefi_print_string
+  call os_print_string
 
   ret
 
@@ -172,10 +163,10 @@ uefi_read_char:
 ;;
 ;; Inputs:
 ;; - RCX = Error code
-uefi_terminate:
+os_terminate:
   mov rcx, terminated_msg
   mov rdx, terminated_msg.len
-  call uefi_print_string
+  call os_print_string
   jmp $
 
 section '.data' readable writable
@@ -185,7 +176,7 @@ system_table dq ? ; EFI_SYSTEM_TABLE*
 terminated_msg db 0xD, 0xA, '(The program has terminated.)', 0xD, 0xA
 .len = $ - terminated_msg
 
-uefi_print_string.output_buffer rq 0x400
+os_print_string.output_buffer rq 0x400
 
 char_buffer db ?
 
-- 
2.39.2