Add number flag

src/mod.S

@@ -0,0 +1,134 @@
+.data
+line_count:     .space 8
+
+.section .text
+.globl add_endings, add_line_numbers
+
+# Print to stdout while adding "$" characters.
+# @param[in] a0: ptr to null-terminated str.
+# @param[in] a1: length of str.
+# @param[in] a2: mod buf addr.
+# @param[out] a0: result code.
+# @param[out] a1: bytes written to mod buf.
+add_endings:
+    addi sp, sp, -72
+    sd s7, 64(sp)
+    sd s6, 56(sp)
+    sd s5, 48(sp)
+    sd s4, 40(sp)
+    sd ra, 32(sp)
+    sd s3, 24(sp)
+    sd s2, 16(sp)
+    sd s1, 8(sp)
+    sd s0, 0(sp)
+
+
+    mv s0, a0 # put the str buf ptr in s0
+    mv s1, a1
+    li s2, 0 # set the str buf char counter to 0
+    li s3, 0 # set the mod buf char counter to 0
+    
+    mv s5, a2
+    .LEndingsProcessChunk:
+    add s4, s0, s2 # Calculate the offset address
+    lb t6, 0(s4)
+    li t4, 0xA # newline
+    bne t6, t4, 1f # if the current byte is not a newline, skip to writing
+
+    add s4, s5, s3 # s4 = mod buf[s2]
+    li t5, '$'
+    sb t5, 0(s4) # mod buf[s2] = $
+    li t5, '\n'
+    addi s4, s4, 1
+    sb t5, 0(s4) # mod buf[s2] = \n
+    addi s3, s3, 2
+    j 2f
+
+    1:
+    add s4, s5, s3 # s4 = mod buf[s2]
+    sb t6, 0(s4) # mod buf[s2] = t6
+
+    addi s3, s3, 1 # inc mod buf pointer
+    2:
+    addi s2, s2, 1 # inc str buf pointer
+    blt s2, s1, .LEndingsProcessChunk
+
+    li a0, 0
+    mv a1, s3
+
+    ld s0, 0(sp)
+    ld s1, 8(sp)
+    ld s2, 16(sp)
+    ld s3, 24(sp)
+    ld ra, 32(sp)
+    ld s4, 40(sp)
+    ld s5, 48(sp)
+    ld s6, 56(sp)
+    ld s7, 64(sp)
+    addi sp, sp, 72
+    ret
+
+# Prefix newlines with ######+TAB line count
+# @param[in] a0: ptr to null-terminated str.
+# @param[in] a1: length of str.
+# @param[in] a2: mod buf addr.
+# @param[in] a3: skip empty.
+# @param[out] a0: result code.
+# @param[out] a1: bytes written to mod buf.
+add_line_numbers:
+    addi sp, sp, -72
+    sd s7, 64(sp)
+    sd s6, 56(sp)
+    sd s5, 48(sp)
+    sd s4, 40(sp)
+    sd ra, 32(sp)
+    sd s3, 24(sp)
+    sd s2, 16(sp)
+    sd s1, 8(sp)
+    sd s0, 0(sp)
+
+
+    mv s0, a0 # put the str ptr in s0
+    mv s1, a1
+    li s2, 0 # set the str buf char counter to 0
+    li s3, 0 # set the mod buf char counter to 0
+    
+    mv s5, a2
+    .LLineNumbersProcessChunk:
+    add s4, s0, s2 # Calculate the offset address
+    lb t6, 0(s4)
+    li t4, 0xA # newline
+    bne t6, t4, 1f # if the current byte is not a newline, skip to writing
+
+    add s4, s5, s3 # move modbuf pointer
+    li t5, '\n'
+    sb t5, 0(s4) # mod buf[s2] = \n
+
+    addi s4, s4, 1
+    addi s3, s3, 1
+    j 2f
+
+    1:
+    add s4, s5, s3 # s4 = mod buf[s2]
+    sb t6, 0(s4) # mod buf[s2] = t6
+
+    addi s3, s3, 1 # inc mod buf pointer
+    2:
+    addi s2, s2, 1 # inc str buf pointer
+    blt s2, s1, .LLineNumbersProcessChunk
+
+    li a0, 0
+    mv a1, s3
+
+    ld s0, 0(sp)
+    ld s1, 8(sp)
+    ld s2, 16(sp)
+    ld s3, 24(sp)
+    ld ra, 32(sp)
+    ld s4, 40(sp)
+    ld s5, 48(sp)
+    ld s6, 56(sp)
+    ld s7, 64(sp)
+    addi sp, sp, 72
+    ret
+