foo

[ld45_start_nothing] / src / dbglog.asm

diff --git a/src/dbglog.asm b/src/dbglog.asm
new file mode 100644 (file)
index 0000000..0753631
--- /dev/null
+++ b/src/dbglog.asm
@@ -0,0 +1,67 @@
+; vi:filetype=nasm ts=8 sts=8 sw=8:
+       section .text
+
+       ; expects the address of a zero-terminated string in esi
+       global dbglog_str
+dbglog_str:
+       mov al, [esi]
+       cmp al, 0
+       jz .end
+       inc esi
+       call ser_putchar
+       jmp dbglog_str
+.end:  ret
+
+       global dbglog_str_num
+dbglog_str_num:
+       pusha
+       call dbglog_str
+       mov eax, [esp + 28]     ; eax pushed by pusha
+
+       mov esi, numbuf + 16
+       mov byte [esi], 0
+       mov ebx, 10
+.convloop:
+       xor edx, edx
+       div ebx
+       add dl, '0'
+       dec esi
+       mov [esi], dl
+       cmp eax, 0
+       jnz .convloop
+
+       call dbglog_str
+       popa
+       ret
+
+
+UART_DATA equ 3f8h
+UART_LSTAT equ 3fdh
+LST_TREG_EMPTY equ 20h
+
+ser_putchar:
+       push edx
+       cmp al, 10
+       jnz .notlf
+       push eax
+       mov al, 13
+       call ser_putchar
+       pop eax
+
+.notlf:        mov ah, al
+       ; wait until the transmit register is empty
+       mov dx, UART_LSTAT
+.wait: in al, dx
+       and al, LST_TREG_EMPTY
+       jz .wait
+       mov dx, UART_DATA
+       mov al, ah
+       out dx, al
+
+       pop edx
+       ret
+
+
+
+       section .data
+numbuf: times 16 db 0