Lecture 109 - Implementing the ability to read lines

nibblebits · Dec 16, 2020 · bea44ff · bea44ff
1 parent b10cefb
commit bea44ff
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Showing 5 changed files with 66 additions and 12 deletions.
diff --git a/programs/blank/blank.c b/programs/blank/blank.c
@@ -15,12 +15,13 @@ int main(int argc, char** argv)
     void* ptr = malloc(512);
     free(ptr);
 
+    char buf[1024];
+    peachos_terminal_readline(buf, sizeof(buf), true);
+
+    print(buf);
+
     while(1) 
     {
-        if (getkey() != 0)
-        {
-            print("key was pressed\n");
-        }
     }
     return 0;
 }
diff --git a/programs/stdlib/Makefile b/programs/stdlib/Makefile
@@ -1,15 +1,18 @@
-FILES=./build/start.o ./build/peachos.o ./build/stdlib.o ./build/stdio.o
+FILES=./build/start.o ./build/peachos.asm.o ./build/peachos.o ./build/stdlib.o ./build/stdio.o
 INCLUDES=-I./src
-FLAGS= -g -falign-jumps -falign-functions -falign-labels -falign-loops -fstrength-reduce -fomit-frame-pointer -finline-functions -Wno-unused-function -fno-builtin -Werror -Wno-unused-label -Wno-cpp -Wno-unused-parameter -nostdlib -nostartfiles -nodefaultlibs -Wall -O0 -Iinc
+FLAGS= -g -ffreestanding -falign-jumps -falign-functions -falign-labels -falign-loops -fstrength-reduce -fomit-frame-pointer -finline-functions -Wno-unused-function -fno-builtin -Werror -Wno-unused-label -Wno-cpp -Wno-unused-parameter -nostdlib -nostartfiles -nodefaultlibs -Wall -O0 -Iinc
 
 all: ${FILES}
 	i686-elf-ld -m elf_i386 -relocatable ${FILES} -o ./stdlib.elf
 
 ./build/start.o: ./src/start.asm
 	nasm -f elf ./src/start.asm -o ./build/start.o
 
-./build/peachos.o: ./src/peachos.asm
-	nasm -f elf ./src/peachos.asm -o ./build/peachos.o
+./build/peachos.asm.o: ./src/peachos.asm
+	nasm -f elf ./src/peachos.asm -o ./build/peachos.asm.o
+
+./build/peachos.o: ./src/peachos.c
+	i686-elf-gcc ${INCLUDES} $(FLAGS) -std=gnu99 -c ./src/peachos.c -o ./build/peachos.o
 
 ./build/stdlib.o: ./src/stdlib.c
 	i686-elf-gcc ${INCLUDES} $(FLAGS) -std=gnu99 -c ./src/stdlib.c -o ./build/stdlib.o

diff --git a/programs/stdlib/src/peachos.asm b/programs/stdlib/src/peachos.asm
@@ -3,7 +3,7 @@
 section .asm
 
 global print:function
-global getkey:function
+global peachos_getkey:function
 global peachos_malloc:function
 global peachos_free:function
 global peachos_putchar:function
@@ -19,8 +19,8 @@ print:
     pop ebp
     ret
 
-; int getkey()
-getkey:
+; int peachos_getkey()
+peachos_getkey:
     push ebp
     mov ebp, esp
     mov eax, 2 ; Command getkey

diff --git a/programs/stdlib/src/peachos.c b/programs/stdlib/src/peachos.c
@@ -0,0 +1,46 @@
+#include "peachos.h"
+
+int peachos_getkeyblock()
+{
+    int val = 0;
+    do
+    {
+        val = peachos_getkey();
+    }
+    while(val == 0);
+    return val;
+}
+
+void peachos_terminal_readline(char* out, int max, bool output_while_typing)
+{
+    int i = 0;
+    for (i = 0; i < max -1; i++)
+    {
+        char key = peachos_getkeyblock();
+
+        // Carriage return means we have read the line
+        if (key == 13)
+        {
+            break;
+        }
+
+        if (output_while_typing)
+        {
+            peachos_putchar(key);
+        }
+
+        // Backspace
+        if (key == 0x08 && i >= 1)
+        {
+            out[i-1] = 0x00;
+            // -2 because we will +1 when we go to the continue
+            i -= 2;
+            continue;
+        }
+
+        out[i] = key;
+    }
+
+    // Add the null terminator
+    out[i] = 0x00;
+}
diff --git a/programs/stdlib/src/peachos.h b/programs/stdlib/src/peachos.h
@@ -1,12 +1,16 @@
 #ifndef PEACHOS_H
 #define PEACHOS_H
 #include <stddef.h>
+#include <stdbool.h>
 
 void print(const char* filename);
-int getkey();
+int peachos_getkey();
 
 void* peachos_malloc(size_t size);
 void peachos_free(void* ptr);
 void peachos_putchar(char c);
+int peachos_getkeyblock();
+void peachos_terminal_readline(char* out, int max, bool output_while_typing);
+
 
 #endif