Improved SCons script for building the userspace stdlib.

targets/x86_64/SConscript

@@ -24,16 +24,14 @@ def get_crt_object(name: str) -> str:
 
 crtbegin_o = get_crt_object('crtbegin.o')
 crtend_o = get_crt_object('crtend.o')
-crti_o = kernel_env.Object('src/crt/crti.s')
-crtn_o = kernel_env.Object('src/crt/crtn.s')
+crti_o = kernel_env.Object(kernel_env['CRTI_PATH'])
+crtn_o = kernel_env.Object(kernel_env['CRTN_PATH'])
 kernel_env['LINKCOM'] = env['LINKCOM'].replace('$_LIBFLAGS', f'{crti_o[0].abspath} {crtbegin_o} -Wl,--start-group $_LIBFLAGS -Wl,--end-group -lgcc {crtend_o} {crtn_o[0].abspath}')
 
 kernel_isr_sources = env['KERNEL_ISR_SOURCES'] + Split('''
 
 ''')
 kernel_sources = env['KERNEL_SOURCES'] + Split('''
-    src/cstdlib/memory.s
-
     src/kernel/boot.s
     src/kernel/startup.cpp
 ''') + [kernel_env.Object(f, CCFLAGS = kernel_env['CCFLAGS'] + ['-mgeneral-regs-only']) for f in kernel_isr_sources]

targets/x86_64/src/crt/crti.s

@@ -1,16 +0,0 @@
-/* x86_64 crti.s */
-.section .init
-.global _init
-.type _init, @function
-_init:
-	push %rbp
-	movq %rsp, %rbp
-	/* gcc will nicely put the contents of crtbegin.o's .init section here. */
-
-.section .fini
-.global _fini
-.type _fini, @function
-_fini:
-	push %rbp
-	movq %rsp, %rbp
-	/* gcc will nicely put the contents of crtbegin.o's .fini section here. */

targets/x86_64/src/crt/crtn.s

@@ -1,10 +0,0 @@
-/* x86_64 crtn.s */
-.section .init
-	/* gcc will nicely put the contents of crtend.o's .init section here. */
-	popq %rbp
-	ret
-
-.section .fini
-	/* gcc will nicely put the contents of crtend.o's .fini section here. */
-	popq %rbp
-	ret

targets/x86_64/src/cstdlib/memory.s

@@ -1,66 +0,0 @@
-
-.section .text
-.global memcpy
-.type memcpy @function
-
-// void* memcpy(void* dest [%rdi], void* src [%rsi], size_t count [%rdx])
-//
-memcpy:
-    movq %rdi, %rax // return value
-memcpy_qwords:
-    cmpq $8, %rdx      // check if the remaining bytes are at least 8
-    jl memcpy_bytes    // if not copy the remaining bytes per byte
-    movq (%rsi), %rcx  // if yes, copy using movq
-    movq %rcx, (%rdi)
-    addq $8, %rsi
-    addq $8, %rdi
-    subq $8, %rdx
-    jmp memcpy_qwords
-memcpy_bytes:
-    cmpq $0, %rdx
-    je memcpy_end
-    movb (%rsi), %ch
-    movb %ch, (%rdi)
-    addq $1, %rsi
-    addq $1, %rdi
-    subq $1, %rdx
-    jmp memcpy_bytes
-memcpy_end:
-    ret
-
-.global memmove
-.type memmove @function
-// void* memmove(void* dest [%rdi], void* src [%rsi], size_t count [%rdx])
-//
-memmove:
-    movq %rdi, %rax     // preserve dest as return value
-    cmpq %rsi, %rdi     // check if dest > src
-    jg memmove_backward // if yes, do everything backwards
-    movq %rsi, %rcx     // check if (src - dest) < 8
-    subq %rdi, %rcx
-    cmpq $8, %rdi
-    jl memcpy_bytes     // if yes, we have to do a bytewise copy
-    jmp memcpy_qwords   // otherwise copy whole qwords
-memmove_backward:       // dest > src, copy backwards
-    addq %rdx, %rdi     // dest = dest + count
-    addq %rdx, %rsi     // src = src + count
-memmove_qwords:
-    cmpq $8, %rdx        // check if the remaining bytes are at least 8
-    jl memmove_bytes    // if not copy the remaining bytes per byte
-    movq -8(%rsi), %rcx // if yes, copy using movq
-    movq %rcx, -8(%rdi)
-    subq $8, %rsi
-    subq $8, %rdi
-    subq $8, %rdx
-    jmp memmove_qwords
-memmove_bytes:
-    cmpq $0, %rdx
-    je memmove_end
-    movb (%rsi), %ch
-    movb %ch, (%rdi)
-    subq $1, %rsi
-    subq $1, %rdi
-    subq $1, %rdx
-    jmp memmove_bytes
-memmove_end:
-    ret