C userspace programs

ulib/.gitignore

@@ -0,0 +1 @@
+*.o

ulib/Makefile

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+include $(ROOT)/mk/grabsrc.mk
+include $(ROOT)/mk/arch/toolchain-$(ARCH).mk
+include $(ROOT)/mk/user/$(ARCH).mk
+
+.PHONY: all clean
+
+SRCFILES := $(call GRABSRC, \
+							. \
+							syscall \
+							string \
+							system \
+						)
+
+CFLAGS += -isystem $(ROOT)/ulib -isystem $(ROOT)/std/include
+
+ASFILES := $(call GET_ASFILES, $(SRCFILES))
+CFILES := $(call GET_CFILES, $(SRCFILES))
+OBJ := $(call GET_OBJ, $(SRCFILES))
+
+%.o: %.S
+	$(CC) $(CFLAGS) -c $< -o $@
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+libulib.a: $(OBJ)
+	$(AR) rcs libulib.a $(OBJ)
+
+all: libulib.a
+
+clean:
+	rm -f $(OBJ)
+	rm -f libulib.a

ulib/_premain.c

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+#include <stdint.h>
+#include <stddef.h>
+
+extern void main(void);
+
+extern uint8_t _bss_start[];
+extern uint8_t _bss_end[];
+
+void bss_clear(void) {
+  uint8_t *p = _bss_start;
+  while (p != _bss_end) {
+    *p = 0;
+    p++;
+  }
+}
+
+// ulib initialization goes here
+void _premain(void) {
+  bss_clear();
+  main();
+}
+

ulib/_start.S

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+#include <syscall/syscall.h>
+
+.extern _premain
+
+.global _start
+_start:
+  call _premain
+
+  mov $SYS_QUITPROC, %rax
+  int $0x80

ulib/string/string.c

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+#include <stddef.h>
+#include <string/string.h>
+
+size_t string_len(const char *s) {
+  size_t l = 0;
+  while (*s != '\0') {
+    l++;
+    s++;
+  }
+  return l;
+}

ulib/string/string.h

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+#ifndef ULIB_STRING_STRING_H_
+#define ULIB_STRING_STRING_H_
+
+#include <stddef.h>
+
+size_t string_len(const char *s);
+
+#endif // ULIB_STRING_STRING_H_

ulib/syscall/syscall.c

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+#include <stdint.h>
+
+uint64_t syscall(uint64_t num, uint64_t arg1, uint64_t arg2,
+    uint64_t arg3, uint64_t arg4, uint64_t arg5, uint64_t arg6) {
+  uint64_t ret = 0;
+  asm volatile (
+    "mov %[SYSNUM], %%rax\n"
+    "mov %[ARG1], %%rdi\n"
+    "mov %[ARG2], %%rsi\n"
+    "mov %[ARG3], %%rdx\n"
+    "mov %[ARG4], %%r10\n"
+    "mov %[ARG5], %%r8\n"
+    "mov %[ARG6], %%r9\n"
+    "int $0x80\n"
+    "mov %%rax, %[RESULT]\n"
+    : [RESULT]"=r"(ret)
+    : [SYSNUM]"r"(num),
+      [ARG1]"r"(arg1),
+      [ARG2]"r"(arg2),
+      [ARG3]"r"(arg3),
+      [ARG4]"r"(arg4),
+      [ARG5]"r"(arg5),
+      [ARG6]"r"(arg6)
+    : "%rax", "%rdi", "%rsi", "%rdx", "%r10", "%r8", "%r9", "memory"
+  );
+  return ret;
+}

ulib/syscall/syscall.h

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+#ifndef ULIB_SYSCALL_SYSCALL_H_
+#define ULIB_SYSCALL_SYSCALL_H_
+
+#define SYS_DEBUGPRINT  1
+#define SYS_QUITPROC    2
+
+#if !defined(__ASSEMBLER__)
+
+uint64_t syscall(uint64_t num, uint64_t arg1, uint64_t arg2,
+    uint64_t arg3, uint64_t arg4, uint64_t arg5, uint64_t arg6);
+
+#endif // ! __ASSEMBLER__
+
+#endif // ULIB_SYSCALL_SYSCALL_H_

ulib/system/system.c

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+#include <stdint.h>
+#include <system/system.h>
+#include <syscall/syscall.h>
+
+
+void sys_debugprint(const char *string) {
+  syscall(SYS_DEBUGPRINT, (uint64_t)string, 0, 0, 0, 0, 0);
+}
+

ulib/system/system.h

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+#ifndef ULIB_SYSTEM_SYSTEM_H_
+#define ULIB_SYSTEM_SYSTEM_H_
+
+void sys_debugprint(const char *string);
+
+#endif // ULIB_SYSTEM_SYSTEM_H_