kprintf and kprint_float

src/boot/entry.S

@@ -4,12 +4,16 @@ _start:
     la sp, stack_top      # Set up the stack pointer
     la t0, trap_entry     # Set up the trap handler
     csrw mtvec, t0        # Set the trap vector to our trap handler
+    li t0, 0x00006000     # Load the mask for FS bits. enable float
+    csrs mstatus, t0      # Set the FS bits to 11 (Dirty/Initial). enable float
     call kmain            # Jump to our C code
 loop:
     wfi                   # Wait for Interrupt (saves CPU)
     j loop                # Infinite loop if C returns
 .align 4
 trap_entry:
+    csrr a0, mcause    # Argument 1: mcause
+    csrr a1, mepc      # Argument 2: mepc
     j handle_trap
 .section .bss
 .align 16

src/drivers/uart.c

@@ -38,6 +38,22 @@ void kprint_int(int num) {
 	}
 }
 
+void kprint_float(float num) {
+	if (num < 0) {
+		kputchar('-');
+		num = -num;
+	}
+	int int_part = (int)num;
+	float frac_part = num - int_part;
+	kprint_int(int_part);
+	kputchar('.');
+	for (int i = 0; i < 6; i++) {
+		frac_part *= 10.0f;
+	}
+	int fraction = (int)(frac_part + 0.5f); // Round to nearest
+	kprint_int(fraction);
+}
+
 void kprint_hex(uint64_t val) {
     char *digits = "0123456789ABCDEF";
     char buffer[16]; // 64-bit hex is 16 chars
@@ -79,6 +95,11 @@ void kprintf(const char *format, ...) {
 					kprint_int(d);
 					break;
 				}
+				case 'f': {
+					double f = va_arg(args, double);
+					kprint_float((float)f);
+					break;
+				}
 				case 'x':   // Hex
 				case 'p': { // Pointer
 					uint64_t x = va_arg(args, uint64_t);
@@ -97,5 +118,5 @@ void kprintf(const char *format, ...) {
 			kputchar(*p);
 		}
 	}
-
+	knewline();
 }

src/drivers/uart.h

@@ -7,6 +7,7 @@ int kputchar(int ch);
 void kprint_hex(uint64_t val);
 void kprint_int(int num);
 void kprintf(const char *format, ...);
+void kprint_float(float num);
 void knewline();
 void kputs(const char *str);
 void kprint(const char *str);

src/kernel/kernel.c

@@ -6,7 +6,7 @@
 #include <kernel/memory.h>
 
 void kmain() {
-    kputs("Hello, OS World!");
+    kprintf("Hello, from %s v%f!" , "SquidgeOS", 0.5);
     kputs("-------------------");
     knewline();
     page_init();