1 files changed, 86 insertions, 0 deletions
diff --git a/src/lib/tub2tsv.s b/src/lib/tub2tsv.s
new file mode 100644
index 0000000..558c51e
--- /dev/null
+++ b/src/lib/tub2tsv.s
@@ -0,0 +1,86 @@
+# --------------------------------------------
+# FUNCTION: tub2tsv
+# PURPOSE : take a buffer of coordinates
+#           and print each coordinate on a line
+# INPUTS  : rdi = pointer to buffer,
+#           rsi = number of coordinates
+# OUTPUTS : rax = address to string of tab seperated values
+#           rdx = number of bytes
+# CLOBBERS: 
+# --------------------------------------------
+.section .text
+.globl tub2tsv
+.type tub2tsv, @function
+tub2tsv:
+    # save callee-saved registers
+    pushq %r12
+    pushq %r13
+    pushq %r14
+    pushq %r15
+    pushq %rbx
+
+    movq %rdi, %r12                 # r12 = address to array of coordinates
+    movq %rsi, %r13                 # r13 = count of coordinates
+
+    # allocate memory based on number of coordinates and max integer size
+    # maybe allocate in chunks might be better, as to waste less memory
+    movq %rsi, %rdi
+    imulq $42, %rdi                 # 20 bytes for each coordindate + tab
+    incq %rdi                       # +1 byte for null terminator
+    call allocate
+    movq %rax, %r14                 # r14 = output buffer start
+    movq %rax, %r15                 # r15 = current write pos
+
+    xorq %rbx, %rbx                 # loop counter
+
+.tub2tsv_loop:
+    cmpq %r13, %rbx                 # if loop counter >= count of coordinates
+    jge .tub2tsv_exit               # done
+    
+    # get addrss to current tuple
+    movq (%r12, %rbx, 8), %rdi      # rdi = array[loop counter]
+    pushq %rdi                      # save pointer to current tuple
+
+    # convert first integer to ASCII
+    movq (%rdi), %rdi               # rdi = first int
+    movq %r15, %rsi                 # rsi = current write pos
+    call int2str                    # rax = string start, rdx = length
+    addq %rdx, %r15                 # advance write pos with num bytes written 
+    
+    # write tab
+    movb $'\t', (%r15)
+    incq %r15 
+
+    # convert second integer to ASCII
+    popq %rdi                       # restore pointer to tuple
+    movq 8(%rdi), %rdi              # rdi = second int
+    movq %r15, %rsi                 # rsi = current write pos
+    call int2str                    # rax = string start, rdx = length
+    addq %rdx, %r15                 # advance write pos with num bytes written
+
+    # write newline
+    movb $'\n', (%r15)
+    incq %r15 
+
+    incq %rbx
+    jmp .tub2tsv_loop
+
+.tub2tsv_exit:
+    # add null terminator
+    movb $0, (%r15)
+
+    # move address to output register
+    movq %r14, %rax
+
+    # return length in rdx
+    movq %r15, %rdx
+    subq %r14, %rdx
+
+    # restore callee-saved registers
+    popq %rbx
+    popq %r15
+    popq %r14
+    popq %r13
+    popq %r12
+
+    ret