Implemented printf!

src/bootloader/stage2/Makefile

@@ -1,9 +1,8 @@
 BUILD_DIR?=build/
 ASM?=nasm
 ASMFLAGS?=-f obj
-CC?=gcc
 CC16?=/usr/bin/watcom/binl/wcc
-CFLAGS16?= -4 -d3 -s -wx -ms -zl -zq
+CFLAGS16?=-4 -d3 -s -wx -ms -zl -zq # -oneatxzh 
 LD16?=/usr/bin/watcom/binl/wlink
 
 SOURCES_C=$(wildcard *.c)
@@ -11,7 +10,7 @@ SOURCES_ASM=$(wildcard *.asm)
 OBJECTS_C=$(patsubst %.c, $(BUILD_DIR)/stage2/c/%.obj, $(SOURCES_C))
 OBJECTS_ASM=$(patsubst %.asm, $(BUILD_DIR)/stage2/asm/%.obj, $(SOURCES_ASM))
 
-.PHONY: all clean always
+.PHONY: all stage2 clean always
 
 all: stage2
 

src/bootloader/stage2/linker.lnk

@@ -4,7 +4,7 @@ OPTION QUIET,
        START=entry,
        VERBOSE,
        OFFSET=0,
-    STACK=0X200
+       STACK=0x200
 ORDER
     CLNAME CODE
         SEGMENT _ENTRY

src/bootloader/stage2/main.asm

@@ -0,0 +1,22 @@
+bits 16
+
+section _ENTRY class=CODE
+
+extern _cstart_
+global entry
+
+entry:
+    cli
+
+    mov ax, ds
+    mov ss, ax
+    mov sp, 0
+    mov bp, sp
+    sti
+
+    xor dh, dh
+    push dx
+    call _cstart_
+
+    cli
+    hlt

src/bootloader/stage2/main.c

@@ -3,6 +3,11 @@
 
 void _cdecl cstart_(uint16_t bootDrive)
 {
-    puts("Hello World from the Stage 2 of the bootloader written in C!");
+    const char far* far_str = "far string";
+
+    puts("Hello world from stage 2 of the bootloader written in C!\r\n");
+    printf("Formatted %% %c %s %ls\r\n", 'a', "string", far_str);
+    printf("Formatted %d %i %x %p %o %hd %hi %hhu %hhd\r\n", 1234, -5678, 0xdead, 0xbeef, 012345, (short)27, (short)-42, (unsigned char)20, (signed char)-10);
+    printf("Formatted %ld %lx %lld %llx\r\n", -100000000l, 0xdeadbeeful, 10200300400ll, 0xdeadbeeffeebdaedull);
     for (;;);
 }

src/bootloader/stage2/stdint.h

@@ -6,9 +6,12 @@ typedef signed short int16_t;
 typedef unsigned short uint16_t;
 typedef signed long int int32_t;
 typedef unsigned long int uint32_t;
-typedef signed long int int64_t;
+typedef signed long long int int64_t;
-typedef unsigned long int uint64_t;
+typedef unsigned long long int uint64_t;
+
 typedef uint8_t bool;
 
-#define true 1
 #define false 0
+#define true 1
+
+

src/bootloader/stage2/stdio.c

@@ -5,6 +5,7 @@ void putc(char c)
 {
     x86_Video_WriteCharTeletype(c, 0);
 }
+
 void puts(const char* str)
 {
     while(*str)
@@ -14,6 +15,15 @@ void puts(const char *str)
     }
 }
 
+void puts_f(const char far* str)
+{
+    while(*str)
+    {
+        putc(*str);
+        str++;
+    }
+}
+
 #define PRINTF_STATE_NORMAL         0
 #define PRINTF_STATE_LENGTH         1
 #define PRINTF_STATE_LENGTH_SHORT   2
@@ -45,11 +55,9 @@ void _cdecl printf(const char *fmt, ...)
             case PRINTF_STATE_NORMAL:
                 switch (*fmt)
                 {
-            case '%':
+                    case '%':   state = PRINTF_STATE_LENGTH;
-                state = PRINTF_STATE_LENGTH;
                                 break;
-            default:
+                    default:    putc(*fmt);
-                putc(*fmt);
                                 break;
                 }
                 break;
@@ -57,16 +65,13 @@ void _cdecl printf(const char *fmt, ...)
             case PRINTF_STATE_LENGTH:
                 switch (*fmt)
                 {
-            case 'h':
+                    case 'h':   length = PRINTF_LENGTH_SHORT;
-                length = PRINTF_LENGTH_SHORT;
                                 state = PRINTF_STATE_LENGTH_SHORT;
                                 break;
-            case 'l':
+                    case 'l':   length = PRINTF_LENGTH_LONG;
-                length = PRINTF_LENGTH_LONG;
                                 state = PRINTF_STATE_LENGTH_LONG;
                                 break;
-            default:
+                    default:    goto PRINTF_STATE_SPEC_;
-                goto PRINTF_STATE_SPEC_;
                 }
                 break;
 
@@ -76,8 +81,7 @@ void _cdecl printf(const char *fmt, ...)
                     length = PRINTF_LENGTH_SHORT_SHORT;
                     state = PRINTF_STATE_SPEC;
                 }
-            else
+                else goto PRINTF_STATE_SPEC_;
-                goto PRINTF_STATE_SPEC_;
                 break;
 
             case PRINTF_STATE_LENGTH_LONG:
@@ -86,21 +90,18 @@ void _cdecl printf(const char *fmt, ...)
                     length = PRINTF_LENGTH_LONG_LONG;
                     state = PRINTF_STATE_SPEC;
                 }
-            else
+                else goto PRINTF_STATE_SPEC_;
-                goto PRINTF_STATE_SPEC_;
                 break;
 
             case PRINTF_STATE_SPEC:
             PRINTF_STATE_SPEC_:
                 switch (*fmt)
                 {
-            case 'c':
+                    case 'c':   putc((char)*argp);
-                putc((char)*argp);
                                 argp++;
                                 break;
 
-            case 's':
+                    case 's':   if (length == PRINTF_LENGTH_LONG || length == PRINTF_LENGTH_LONG_LONG)
-                if (length == PRINTF_LENGTH_LONG || length == PRINTF_LENGTH_LONG_LONG)
                                 {
                                     puts_f(*(const char far**)argp);
                                     argp += 2;
@@ -112,43 +113,31 @@ void _cdecl printf(const char *fmt, ...)
                                 }
                                 break;
 
-            case '%':
+                    case '%':   putc('%');
-                putc('%');
                                 break;
 
                     case 'd':
-            case 'i':
+                    case 'i':   radix = 10; sign = true;
-                radix = 10;
-                sign = true;
                                 argp = printf_number(argp, length, sign, radix);
                                 break;
 
-            case 'u':
+                    case 'u':   radix = 10; sign = false;
-                radix = 10;
-                sign = false;
                                 argp = printf_number(argp, length, sign, radix);
                                 break;
 
                     case 'X':
                     case 'x':
-            case 'p':
+                    case 'p':   radix = 16; sign = false;
-                radix = 16;
-                sign = false;
                                 argp = printf_number(argp, length, sign, radix);
                                 break;
 
-            case 'o':
+                    case 'o':   radix = 8; sign = false;
-                radix = 8;
-                sign = false;
                                 argp = printf_number(argp, length, sign, radix);
                                 break;
 
-            // ignore invalid spec
+                    default:    break;
-            default:
-                break;
                 }
 
-            // reset state
                 state = PRINTF_STATE_NORMAL;
                 length = PRINTF_LENGTH_DEFAULT;
                 radix = 10;
@@ -169,7 +158,6 @@ int *printf_number(int *argp, int length, bool sign, int radix)
     int number_sign = 1;
     int pos = 0;
 
-    // process length
     switch (length)
     {
         case PRINTF_LENGTH_SHORT_SHORT:
@@ -229,19 +217,16 @@ int *printf_number(int *argp, int length, bool sign, int radix)
             break;
     }
 
-    // convert number to ASCII
     do
     {
-        uint32_t rem = number % radix;
+        uint32_t rem;
-        number = number / radix;
+        x86_div64_32(number, radix, &number, &rem);
         buffer[pos++] = g_HexChars[rem];
     } while (number > 0);
 
-    // add sign
     if (sign && number_sign < 0)
         buffer[pos++] = '-';
 
-    // print number in reverse order
     while (--pos >= 0)
         putc(buffer[pos]);
 

src/bootloader/stage2/stdio.h

@@ -2,4 +2,5 @@
 
 void putc(char c);
 void puts(const char* str);
+void puts_f(const char far* str);
 void _cdecl printf(const char* fmt, ...);

src/bootloader/stage2/x86.asm

@@ -25,3 +25,24 @@ _x86_Video_WriteCharTeletype:
 global _x86_div64_32
 
 _x86_div64_32:
+    push bp
+    mov bp, sp
+
+    push bx
+    mov eax, [bp + 4]
+    mov ecx, [bp + 12]
+    xor edx, edx
+    div ecx
+    mov bx, [bp + 16]
+    mov [bx + 4], eax
+    mov eax, [bp + 4]
+    div ecx
+    mov [bx], eax
+    mov bx, [bp + 18]
+    mov [bx], edx
+    pop bx
+
+    mov sp, bp
+    pop bp
+
+    ret

src/bootloader/stage2/x86.h

@@ -1,5 +1,6 @@
 #pragma once
 #include "stdint.h"
 
+void _cdecl x86_div64_32(uint64_t dividend, uint32_t divisor, uint64_t* quotientOut, uint32_t* remainderOut);
+
 void _cdecl x86_Video_WriteCharTeletype(char c, uint8_t page);
-void _cdecl x86_div64_32(uint64_t dividend, uint32_t divisor, uint64_t *quotientOut, uint64_t *remainderOut);