first commit

.clang-format

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+BasedOnStyle: WebKit
+IndentWidth: 4
+TabWidth: 4
+UseTab: Never
+AlignConsecutiveDeclarations: false
+AlignConsecutiveAssignments: false
+AlignTrailingComments: true
+ColumnLimit: 105
+BreakBeforeBraces: Attach
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: false
+AllowShortLambdasOnASingleLine: false
+PointerAlignment: Left
+SpaceBeforeParens: Never
+SpacesInParentheses: false
+SpacesInConditionalStatement: false
+SpacesInContainerLiterals: false
+SpaceAfterCStyleCast: false
+SpaceBeforeCpp11BracedList: false
+SpaceBeforeSquareBrackets: false
+SpacesBeforeTrailingComments: 2
+PenaltyBreakAssignment: 1000
+NamespaceIndentation: All
+

Makefile

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+CC=riscv64-linux-gnu-gcc
+FILES=main.c transform.s
+BINARY=transform
+
+$(BINARY): $(FILES)
+	$(CC) -o $(BINARY) $(FILES)
+
+run: $(BINARY)
+	./$(BINARY) 127.0.0.1
+
+clean:
+	rm $(BINARY)

main.c

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+#include "transform.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char** argv) {
+    if(argc < 2) {
+        fprintf(stderr, "usage: %s <ip>\n", argv[0]);
+        return 1;
+    }
+
+    char* result = transform(argv[1]);
+    if(result == NULL) {
+        fprintf(stderr, "Failed to allocate buffer\n");
+        return 1;
+    }
+
+    printf("%s\n", result);
+    free(result);
+}

transform.h

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+#ifndef TRANSFORM_H
+#define TRANSFORM_H
+
+extern char* transform(char* str);
+
+#endif

transform.s

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+.globl transform
+.extern strlen
+.extern malloc
+
+# this stuff didnt really need to be a macro but whatever
+.macro begin_func
+                      # regs  reg size  return address  16 byte align padding
+    addi sp, sp, -112 # 12  * 8       + 8             + 8
+    sd ra, 104(sp)
+    sd s0, 96(sp)
+    sd s1, 88(sp)
+    sd s2, 80(sp)
+    sd s3, 72(sp)
+    sd s4, 64(sp)
+    sd s5, 56(sp)
+    sd s6, 48(sp)
+    sd s7, 40(sp)
+    sd s8, 32(sp)
+    sd s9, 24(sp)
+    sd s10, 16(sp)
+    sd s11, 8(sp)
+.endm
+
+.macro end_func
+    ld ra, 104(sp)
+    ld s0, 96(sp)
+    ld s1, 88(sp)
+    ld s2, 80(sp)
+    ld s3, 72(sp)
+    ld s4, 64(sp)
+    ld s5, 56(sp)
+    ld s6, 48(sp)
+    ld s7, 40(sp)
+    ld s8, 32(sp)
+    ld s9, 24(sp)
+    ld s10, 16(sp)
+    ld s11, 8(sp)
+    addi sp, sp, 112
+    ret
+.endm
+
+.section .text
+transform:
+    begin_func
+
+    # s0 = input ip pointer
+    # s1 = input length
+    # s2 = buffer length
+    # s3 = buffer pointer
+    mv s0, a0
+    call strlen
+    mv s1, a0
+
+    li t0, 3
+    mul s2, s1, t0 # multiply input length by 3 to get maximum possible output length
+
+    mv a0, s2
+    addi a0, a0, 1 # add space for null terminator
+    call malloc
+    mv s3, a0
+    beq s3, x0, .exit # if allocation failed exit the function
+
+    mv t0, x0 # i
+    mv t1, x0 # out_i
+.loop_start:
+    bge t0, s1, .loop_end # if i == len finish looping
+
+    add t2, s0, t0 # t2 = ip + i
+    lb t3, 0(t2) # t3 has the char
+    li t5, '.'
+    bne t3, t5, .store_char # if the period isnt present skip adding the [
+    
+    add t4, s3, t1 # t4 = buf + out_i
+    li t6, '['
+    sb t6, 0(t4) # *t4 = '['
+    addi t1, t1, 1
+
+.store_char:
+    add t4, s3, t1 # t4 = buf + out_i
+    sb t3, 0(t4) # *t4 = t3 (the current char)
+    addi t0, t0, 1
+    addi t1, t1, 1
+    
+    bne t3, t5, .loop_start # if the period isnt present go back to start of loop
+
+    add t4, s3, t1 # t4 = buf + out_i
+    li t6, ']'
+    sb t6, 0(t4) # *t4 = ']'
+    addi t1, t1, 1
+
+    j .loop_start
+
+.loop_end:
+    addi t4, t4, 1
+    sb x0, 0(t4) # add null terminator
+
+.exit:
+    mv a0, s3 # put buffer into return register
+    end_func