diff options
| author | Christian Cunningham <cc@localhost> | 2022-03-17 20:20:32 -0700 |
|---|---|---|
| committer | Christian Cunningham <cc@localhost> | 2022-03-17 20:20:32 -0700 |
| commit | 51fce9b7a95155347e047f64cac418d895f82fd5 (patch) | |
| tree | 79b5ab4a68e3f98c0e1042ca47c378688650ea37 /src | |
| parent | fa64046e54f5af3d482d2dbcb2dcbff3458a952a (diff) | |
Implemented Semaphore
Relative Address SVC jumps
Diffstat (limited to 'src')
| -rw-r--r-- | src/exceptions/svc.S | 56 |
1 files changed, 43 insertions, 13 deletions
diff --git a/src/exceptions/svc.S b/src/exceptions/svc.S index 88716db..a95c7a6 100644 --- a/src/exceptions/svc.S +++ b/src/exceptions/svc.S @@ -6,20 +6,12 @@ svc: // Get the SVC Exception # ldr r0, [lr, #-4] bic r0, #0xFF000000 - // Jump to the appropriate Call - cmp r0, #5 + cmp r0, #7 + // Check it is within our defined SVC bgt svc_exit - beq svc_000005 - cmp r0, #4 - beq svc_000004 - cmp r0, #3 - beq svc_000003 - cmp r0, #2 - beq svc_000002 - cmp r0, #1 - beq svc_000001 - cmp r0, #0 - beq svc_000000 + //// Jump to the appropriate Call + adr r3, svc_table + ldr pc, [r3, r0, LSL #2] svc_000000: // SYS_YIELD bl yield ldmfd sp!, {r0-r12,lr} @@ -79,5 +71,43 @@ svc_000005: // Release Lock ldmfd sp!, {r0-r12,lr} b schedule b svc_exit +svc_000006: // Semaphore decrease + ldr r0, [sp, #0] // struct Semaphore* s +1: clrex + ldrex r2, [r0, #0] + cmp r2, #0 + beq svc_000006_delay_semaphore + sub r1, r2, #1 + strexeq r2, r1, [r0, #0] + teq r2, #0 + bne 1b + dmb + b svc_exit +svc_000006_delay_semaphore: + bl sched_semaphore_yield + ldmfd sp!, {r0-r12,lr} + sub lr, #4 + b schedule +svc_000007: // Semaphore increase + ldr r0, [sp, #0] // struct Semaphore* s +1: clrex + ldrex r2, [r0, #0] + add r1, r2, #1 + strexeq r2, r1, [r0, #0] + teq r2, #0 + bne 1b + dmb + bl sched_semaphore_resurrect + b svc_exit svc_exit: ldmfd sp!, {r0-r12,pc}^ + +svc_table: + .word svc_000000 + .word svc_000001 + .word svc_000002 + .word svc_000003 + .word svc_000004 + .word svc_000005 + .word svc_000006 + .word svc_000007 |