Unknown systen call: 4242
After printing the error message, the program should exit See the section on halting for more details. Registers AI. 32 registers. Plus Hi and Lo are set to be zero when execution begins. The other 31 registers have no special meaning and can be used for any purpose. The value of register SO (Szao) is always D. Instructions that attempt to change it have no effect The values of registers 52 (Se0) and 54 (SA are used by the syscall instruction. Hi and to are used by the KILT and DIV instructions. And can only be accessed by the MFHI and MFLO instructions.
Execution halts if an exit syscall (syscall 10) is executed. Execution halts if it reaches the location after the last instruction. Execution halts if there is a branch to the location immediately after the last instruction. Execution halts with an error message if there is a branch to any other location beyond the range of specified instructions: Illegal branch to non-instruction: PC = ?? Execution halts after printing an error message. eg: for an invalid syscall number or invalid instruction.
Converting MIPS Assembler Instruction codes
The cornmano 1521 nipa2hen will give )04 the nex coces for %I PS instructions.
S cat examples/42.s main: 11 Sae, 42 11 Sve, 1 syscall
printe(“Xcl”, 42);
11 Sae, ‘ n ‘ a prIntf(“Xc”, n’ ); 11 See, 11 syscall
Jr Sra S 1521 mips2hex exatoples/41.5 2004032a 20020001 eeeeeeec 20060e0e 20020000 eeeeeeec
1521 mips2hex has a couple of features that it make it easier for you to use MIPS programs as test inputs for nip” . For convenience. 1521 mips2hex translates some common pseudo-instructions, e.g. LI into the instruction codes for real instructions in the subset nlpsc handles. 1521 mips2hex translates a few instructions outside the subset Neese handles to the instruction codes for equivalent real instructions in the subset nlpsc handles. 1521 mips2hex handles branch labels for you. It calculates the branch offset and outputs the instruction codes for the appropriate branch instructions. Also for convenience 1521 mlps2hex deletes the last instruction if it is JR because JR is not in the subset for this assignment and a last JR is often just main returning. Note. mlpsc does not need to implement pseudo-instructions or instructions outside the specified subset
Rims The Assignment Reference implementation MIPS Instruction Subset System Calls Registers Halting Converting MIPS Assembler Instruction codes Examples Getting Started Assumptions and Clarifications Change Log Assessment