From 597d15e2341f2a99ba8e699584cef4731583599b Mon Sep 17 00:00:00 2001
From: Byron Lathi <bslathi19@gmail.com>
Date: Wed, 29 Nov 2023 17:19:18 -0800
Subject: [PATCH] Add terminal write as well, use it in kernel

---
 sw/kernel/devices/terminal.s | 24 ++++++++++++++++++++++--
 sw/kernel/kernel.c           | 18 ++++++++++++------
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/sw/kernel/devices/terminal.s b/sw/kernel/devices/terminal.s
index 8afec0f..ea1f0d0 100644
--- a/sw/kernel/devices/terminal.s
+++ b/sw/kernel/devices/terminal.s
@@ -27,7 +27,7 @@ terminal_buf: .res 128
         bge FAIL
         sta tmp1            ; Store nbytes in tmp1
         
-        jsr pushax          ; Check that buf != NULL
+        jsr popax          ; Check that buf != NULL
         cmp #$00
         bne L1
         cpx #$00
@@ -90,14 +90,34 @@ FAIL:   lda #$ff            ; return -1 on fail
         rts
 .endproc
 
-; terminal_write
+; int8_t terminal_write(uint8_t fd, const void* buf, uint8_t nbytes);
 ; write characters to the terminal
 ; Inputs: int8_t* buf - buffer of characters to write
 ;         uint8_t n - number of characters to write
 ; Return Value: 0 on success, -1 on failure
 ; Writes to screen. Only stops after n chars written.
+; This seems to not care about null termination?
 .proc _terminal_write
+        sta tmp1            ; put nbytes in tmp1
 
+        jsr popax           ; check that buf is not null
+        cmp #$00
+        bne L1
+        cpx #$00
+        bne L1
+        bra FAIL
+L1:
+        ldy #$00
+LOOP:   lda (ptr1),y        ; Loop through buffer and print
+        jsr _serial_putc
+        iny
+        cmp tmp1
+        blt LOOP
+        lda #$00
+        rts
+
+FAIL:   lda #$ff            ; old code didn't fail, but new code does.
+        rts
 .endproc
 
 ; terminal_open
diff --git a/sw/kernel/kernel.c b/sw/kernel/kernel.c
index 6c67395..bbdc685 100644
--- a/sw/kernel/kernel.c
+++ b/sw/kernel/kernel.c
@@ -1,10 +1,14 @@
 #include <conio.h>
+#include <string.h>
+
 #include "devices/interrupt_controller.h"
 #include "interrupts/interrupt.h"
 #include "devices/mapper.h"
 #include "devices/rtc.h"
 #include "devices/serial.h"
 
+#include "devices/terminal.h"
+
 
 void handle_rtc_interrupt() {
     // cputs("In IRQ interrupt!\n");
@@ -13,9 +17,9 @@ void handle_rtc_interrupt() {
     asm volatile ("rti");
 }
 
-int main() {
+char buf[128];
 
-    uint8_t c;
+int main() {
 
     cputs("Kernel\n");
 
@@ -40,11 +44,13 @@ int main() {
 
     serial_puts("Hello from serial!\n");
 
+    terminal_open(NULL);
+    terminal_write(0, "Terminal Write\n", 15);
+
     while(1) {
-        c = serial_getc();
-        serial_puts("Got a character!: ");
-        serial_putc(c);
-        serial_putc('\n');
+        terminal_read(0, buf, 128);
+        terminal_write(0, "Got: ", 5);
+        terminal_write(0, buf, strlen(buf));
     }
 
     return 0;