attempts at warmup exercises.

code/warmup/exercise_3.s

@@ -0,0 +1,68 @@
+.psx
+.create "exercise_3.bin", 0x80010000
+
+; Entry Point of Code
+.org 0x80010000
+
+; Constant declaration
+BASE_ADDR equ 0x0000
+
+; Symbol Alias Table
+
+; Instructions
+; Load
+load_imm   equ li ; dst_reg, immeidate value
+; Store
+store_word equ sw ; src_reg, dst_address 
+; Addition
+add_s  equ add   ; dst_reg, reg_a, reg_b (signed)
+add_u  equ add   ; dst_reg, reg_a, reg_b (unsigned)
+add_si equ addi  ; dst_reg, src_reg, immediate value (signed)
+add_ui equ addiu ; dst_reg, src_reg, immediate value (unsigned)
+; Subtraction
+sub_s equ sub    ; 
+sub_u equ subu   ; 
+; Branch
+branch_equal    equ beq ; reg, value(reg, immediate), dst_label
+branch_gt_equal equ bge ; reg, value(reg, immediate), dst_label
+branch_lt       equ blt ; reg, value(reg, immediate), dst_label
+
+; Registers
+; Temporaries, may be changed by subroutines
+rtemp_0 equ $t0
+rtemp_1 equ $t1
+rtemp_2 equ $t2
+
+; /* C code: */
+; main() {
+;  int num;  // Assume num is loaded in $t0
+;  int den;  // Assume den is loaded in $t1
+;  int res;  // Assume res is loaded in $t2
+;  num = 27; // Or any other number that we want
+;  den = 3;  // Or any other number that we want
+;  res = 0;
+;  while (num >= den) {
+;  num -= den;
+;  res++;
+;  }
+; }
+
+main:
+; TODO:
+; 1. Initialize $t0 to 27 (or any other value)
+; 2. Initialize $t1 to 3 (or any other value)
+; 3. Initialize $t2 (res) with 0
+; 4. While ($t0 >= $t1) {
+; 5. Subtract $t0-$t1 and store it back into $t0
+; 6. Increment $t2
+; 7. }
+
+; Attempt:
+	load_imm rtemp_0, 27
+	load_imm rtemp_1, 3
+	load_imm rtemp_2, 0
+	loop: :: branch_lt rtemp_0, rtemp_1, loop_break :: nop ; loop if < rtemp_0, rtemp_1 {
+		sub_s  rtemp_0, rtemp_0, rtemp_1                   ; 	-= rtemp_0, rtemp_1
+		add_si rtemp_2, rtemp_2, 1                         ;    ++ rtemp_2
+	j loop :: loop_break:                                  ; }
+.close