linux libc :

0007764c <strcmp@@GLIBC_2.29>:
   7764c:   00150513            addi    a0,a0,1
   77650:   fff54783            lbu a5,-1(a0)
   77654:   00158593            addi    a1,a1,1
   77658:   fff5c703            lbu a4,-1(a1)
   7765c:   00078863            beqz    a5,7766c <strcmp@@GLIBC_2.29+0x20>
   77660:   fee786e3            beq a5,a4,7764c <strcmp@@GLIBC_2.29>
   77664:   40e78533            sub a0,a5,a4
   77668:   00008067            ret
   7766c:   40e00533            neg a0,a4
   77670:   00008067            ret

baremetal libc:
80000fa8 <strcmp>:
80000fa8:   00b56733            or  a4,a0,a1
80000fac:   fff00393            li  t2,-1
80000fb0:   00377713            andi    a4,a4,3
80000fb4:   10071063            bnez    a4,800010b4 <strcmp+0x10c>
80000fb8:   7f7f87b7            lui a5,0x7f7f8
80000fbc:   f7f78793            addi    a5,a5,-129 # 7f7f7f7f <_stack_size+0x7f7f7b7f>
80000fc0:   00052603            lw  a2,0(a0)
80000fc4:   0005a683            lw  a3,0(a1)
80000fc8:   00f672b3            and t0,a2,a5
80000fcc:   00f66333            or  t1,a2,a5
80000fd0:   00f282b3            add t0,t0,a5
80000fd4:   0062e2b3            or  t0,t0,t1
80000fd8:   10729263            bne t0,t2,800010dc <strcmp+0x134>
80000fdc:   08d61663            bne a2,a3,80001068 <strcmp+0xc0>
80000fe0:   00452603            lw  a2,4(a0)
80000fe4:   0045a683            lw  a3,4(a1)
80000fe8:   00f672b3            and t0,a2,a5
80000fec:   00f66333            or  t1,a2,a5
80000ff0:   00f282b3            add t0,t0,a5
80000ff4:   0062e2b3            or  t0,t0,t1
80000ff8:   0c729e63            bne t0,t2,800010d4 <strcmp+0x12c>
80000ffc:   06d61663            bne a2,a3,80001068 <strcmp+0xc0>
80001000:   00852603            lw  a2,8(a0)
80001004:   0085a683            lw  a3,8(a1)
80001008:   00f672b3            and t0,a2,a5
8000100c:   00f66333            or  t1,a2,a5
80001010:   00f282b3            add t0,t0,a5
80001014:   0062e2b3            or  t0,t0,t1
80001018:   0c729863            bne t0,t2,800010e8 <strcmp+0x140>
8000101c:   04d61663            bne a2,a3,80001068 <strcmp+0xc0>
80001020:   00c52603            lw  a2,12(a0)
80001024:   00c5a683            lw  a3,12(a1)
80001028:   00f672b3            and t0,a2,a5
8000102c:   00f66333            or  t1,a2,a5
80001030:   00f282b3            add t0,t0,a5
80001034:   0062e2b3            or  t0,t0,t1
80001038:   0c729263            bne t0,t2,800010fc <strcmp+0x154>
8000103c:   02d61663            bne a2,a3,80001068 <strcmp+0xc0>
80001040:   01052603            lw  a2,16(a0)
80001044:   0105a683            lw  a3,16(a1)
80001048:   00f672b3            and t0,a2,a5
8000104c:   00f66333            or  t1,a2,a5
80001050:   00f282b3            add t0,t0,a5
80001054:   0062e2b3            or  t0,t0,t1
80001058:   0a729c63            bne t0,t2,80001110 <strcmp+0x168>
8000105c:   01450513            addi    a0,a0,20
80001060:   01458593            addi    a1,a1,20
80001064:   f4d60ee3            beq a2,a3,80000fc0 <strcmp+0x18>
80001068:   01061713            slli    a4,a2,0x10
8000106c:   01069793            slli    a5,a3,0x10
80001070:   00f71e63            bne a4,a5,8000108c <strcmp+0xe4>
80001074:   01065713            srli    a4,a2,0x10
80001078:   0106d793            srli    a5,a3,0x10
8000107c:   40f70533            sub a0,a4,a5
80001080:   0ff57593            andi    a1,a0,255
80001084:   02059063            bnez    a1,800010a4 <strcmp+0xfc>
80001088:   00008067            ret
8000108c:   01075713            srli    a4,a4,0x10
80001090:   0107d793            srli    a5,a5,0x10
80001094:   40f70533            sub a0,a4,a5
80001098:   0ff57593            andi    a1,a0,255
8000109c:   00059463            bnez    a1,800010a4 <strcmp+0xfc>
800010a0:   00008067            ret
800010a4:   0ff77713            andi    a4,a4,255
800010a8:   0ff7f793            andi    a5,a5,255
800010ac:   40f70533            sub a0,a4,a5
800010b0:   00008067            ret
800010b4:   00054603            lbu a2,0(a0)
800010b8:   0005c683            lbu a3,0(a1)
800010bc:   00150513            addi    a0,a0,1
800010c0:   00158593            addi    a1,a1,1
800010c4:   00d61463            bne a2,a3,800010cc <strcmp+0x124>
800010c8:   fe0616e3            bnez    a2,800010b4 <strcmp+0x10c>
800010cc:   40d60533            sub a0,a2,a3
800010d0:   00008067            ret
800010d4:   00450513            addi    a0,a0,4
800010d8:   00458593            addi    a1,a1,4
800010dc:   fcd61ce3            bne a2,a3,800010b4 <strcmp+0x10c>
800010e0:   00000513            li  a0,0
800010e4:   00008067            ret
800010e8:   00850513            addi    a0,a0,8
800010ec:   00858593            addi    a1,a1,8
800010f0:   fcd612e3            bne a2,a3,800010b4 <strcmp+0x10c>
800010f4:   00000513            li  a0,0
800010f8:   00008067            ret
800010fc:   00c50513            addi    a0,a0,12
80001100:   00c58593            addi    a1,a1,12
80001104:   fad618e3            bne a2,a3,800010b4 <strcmp+0x10c>
80001108:   00000513            li  a0,0
8000110c:   00008067            ret
80001110:   01050513            addi    a0,a0,16
80001114:   01058593            addi    a1,a1,16
80001118:   f8d61ee3            bne a2,a3,800010b4 <strcmp+0x10c>
8000111c:   00000513            li  a0,0
80001120:   00008067            ret